Use a consistent placeholder throughout the module

modules/authX509/dictionaries/X509warning.definition.json

 {
   "warning": {
-    "en": "Your certificate will expire in %days% days."
+    "en": "Your certificate will expire in %daysleft% days."
   },
   "warning_header": {
     "en": "Your certificate is about to expire."

modules/authX509/dictionaries/X509warning.translation.json

 {
   "warning": {
-    "nl": "Je certificaat verloopt over %days% dagen.",
-    "no": "Sertifikatet ditt vil utløpe om %days% dager.",
-    "da": "Dit certifikat udløber om %days% dage.",
-    "es": "Su certificado caduca en %days% días.",
-    "el": "\u0397 \u03b9\u03c3\u03c7\u03cd\u03c2 \u03c4\u03bf\u03c5 \u03c0\u03b9\u03c3\u03c4\u03bf\u03c0\u03bf\u03b9\u03b7\u03c4\u03b9\u03ba\u03bf\u03cd \u03c3\u03b1\u03c2 \u03b8\u03b1 \u03bb\u03ae\u03be\u03b5\u03b9 \u03c3\u03b5 %days%."
+    "nl": "Je certificaat verloopt over %daysleft% dagen.",
+    "no": "Sertifikatet ditt vil utløpe om %daysleft% dager.",
+    "da": "Dit certifikat udløber om %daysleft% dage.",
+    "es": "Su certificado caduca en %daysleft% días.",
+    "el": "\u0397 \u03b9\u03c3\u03c7\u03cd\u03c2 \u03c4\u03bf\u03c5 \u03c0\u03b9\u03c3\u03c4\u03bf\u03c0\u03bf\u03b9\u03b7\u03c4\u03b9\u03ba\u03bf\u03cd \u03c3\u03b1\u03c2 \u03b8\u03b1 \u03bb\u03ae\u03be\u03b5\u03b9 \u03c3\u03b5 %daysleft%."
   },
   "warning_header": {
     "nl": "Je certificaat verloopt binnenkort.",

modules/authX509/locales/da/LC_MESSAGES/authX509.po

@@ -34,7 +34,7 @@ msgid "{authX509:X509error:certificate_header}"
 msgstr "X509 certifikat authentifikation"
 
 msgid "{authX509:X509warning:warning}"
-msgstr "Dit certifikat udløber om %days% dage."
+msgstr "Dit certifikat udløber om %daysleft% dage."
 
 msgid "Please renew your certificate in time."
 msgstr "Forny venligst dit certifikat i tide."

modules/authX509/locales/el/LC_MESSAGES/authX509.po

@@ -36,7 +36,7 @@ msgid "{authX509:X509error:certificate_header}"
 msgstr "Ταυτοποίηση μέσω πιστοποιητικού X.509"
 
 msgid "{authX509:X509warning:warning}"
-msgstr "Η ισχύς του πιστοποιητικού σας θα λήξει σε %days%."
+msgstr "Η ισχύς του πιστοποιητικού σας θα λήξει σε %daysleft%."
 
 msgid "Please renew your certificate in time."
 msgstr "Παρακαλείστε να προχωρήσετε σε ανανέωση του πιστοποιητικού σας έγκαιρα."

modules/authX509/locales/en/LC_MESSAGES/authX509.po

@@ -34,7 +34,7 @@ msgid "{authX509:X509error:certificate_header}"
 msgstr "X509 certificate authentication"
 
 msgid "{authX509:X509warning:warning}"
-msgstr "Your certificate will expire in %days% days."
+msgstr "Your certificate will expire in %daysleft% days."
 
 msgid "Please renew your certificate in time."
 msgstr "Please renew your certificate in time."

modules/authX509/locales/es/LC_MESSAGES/authX509.po

@@ -36,7 +36,7 @@ msgid "{authX509:X509error:certificate_header}"
 msgstr "Autenticación mediante certificado X509"
 
 msgid "{authX509:X509warning:warning}"
-msgstr "Su certificado caduca en %days% días."
+msgstr "Su certificado caduca en %daysleft% días."
 
 msgid "Please renew your certificate in time."
 msgstr "Por favor, renueve su certificado a tiempo."

modules/authX509/locales/nb/LC_MESSAGES/authX509.po

@@ -36,7 +36,7 @@ msgid "{authX509:X509error:certificate_header}"
 msgstr "X509 sertifikatautentisering"
 
 msgid "{authX509:X509warning:warning}"
-msgstr "Sertifikatet ditt vil utløpe om %days% dager."
+msgstr "Sertifikatet ditt vil utløpe om %daysleft% dager."
 
 msgid "Please renew your certificate in time."
 msgstr "Vennligst forny sertifikatet ditt før det utløper."

modules/authX509/locales/nl/LC_MESSAGES/authX509.po

@@ -36,7 +36,7 @@ msgid "{authX509:X509error:certificate_header}"
 msgstr "Authenticatie via X509-certificaat"
 
 msgid "{authX509:X509warning:warning}"
-msgstr "Je certificaat verloopt over %days% dagen."
+msgstr "Je certificaat verloopt over %daysleft% dagen."
 
 msgid "Please renew your certificate in time."
 msgstr "Vervang tijdig je certificaat."

modules/authX509/templates/X509warning.php

@@ -11,7 +11,7 @@
  */
 
 $warning = $this->t('{authX509:X509warning:warning}', array(
-    '%days%' => htmlspecialchars($this->data['daysleft']),
+    '%daysleft%' => htmlspecialchars($this->data['daysleft']),
 ));
 
 if( $this->data['renewurl']) {