migration: dismiss popup when error occurs

When something goes wrong before sending the request to the daemon, the
migration popup was not dismissed. It is now the case, and a generic
cancelable error is displayed.

Change-Id: I51b97f7b9fc452ec775e1f4aa849da99badb0862
Tuleap: #1197
diff --git a/ring-android/app/src/main/res/values/strings.xml b/ring-android/app/src/main/res/values/strings.xml
index 60f8389..18f5673 100644
--- a/ring-android/app/src/main/res/values/strings.xml
+++ b/ring-android/app/src/main/res/values/strings.xml
@@ -194,5 +194,7 @@
     <string name="share_message">Scan this QRCode with the embedded scanner of the Ring application that wants to communicate with you.</string>
     <string name="share_message_no_account">Please select an account to share.</string>
     <string name="share_your_account_information">Share my contact information</string>
+    <string name="generic_error_migration">Error</string>
+    <string name="generic_error_migration_message">An error occurred during migration</string>
 
 </resources>