Bug 1427670 - Escape warning message when the user can't write to their profile. r=mhowell

MozReview-Commit-ID: C5ZJd6ZQwzz

--HG--
extra : rebase_source : 32ddd55d2c50a314ad2d0d9c7c2f4e8e8e909632

browser/installer/windows/nsis/stub.nsi

@@ -509,7 +509,7 @@ Function .onInit
 
   Call CanWrite
   ${If} "$CanWriteToInstallDir" == "false"
-    MessageBox MB_OK|MB_ICONEXCLAMATION "$(WARN_WRITE_ACCESS_QUIT)\n\n$INSTDIR"
+    MessageBox MB_OK|MB_ICONEXCLAMATION "$(WARN_WRITE_ACCESS_QUIT)$\n$\n$INSTDIR"
     Quit
   ${EndIf}