bug 1394871 - add key4.db to password-related file list in Firefox profile migration code r=mossop

NSS stores the password encrypting key in key3.db. When Firefox uses the
sqlite-backed NSS databases by default (bug 783994), this file will be called
key4.db. The Firefox profile migration code needs to know this.

MozReview-Commit-ID: 2KgJdZtCXju

--HG--
extra : rebase_source : 0dc88527b787a42951d9b1ba7324378baf0ec3e5

browser/components/migration/FirefoxProfileMigrator.js

@@ -131,7 +131,7 @@ FirefoxProfileMigrator.prototype._getResourcesInternal = function(sourceProfileD
   let favicons = getFileResource(types.HISTORY, ["favicons.sqlite"]);
   let cookies = getFileResource(types.COOKIES, ["cookies.sqlite"]);
   let passwords = getFileResource(types.PASSWORDS,
-    ["signons.sqlite", "logins.json", "key3.db",
+    ["signons.sqlite", "logins.json", "key3.db", "key4.db",
      "signedInUser.json"]);
   let formData = getFileResource(types.FORMDATA, [
     "formhistory.sqlite",