Bug 1394582 - Don't hang forever in the stub installer if the browser was already running. r=agashlin

Fixes a regression from bug 1376597, which caused the stub installer to hang
forever and not respond to the close button if the browser was already running
during the installation.

MozReview-Commit-ID: A1XWGvnlgrS

--HG--
extra : rebase_source : 31d21a3e7c72af874acbebaa30f0f77fc61d555f

browser/installer/windows/nsis/stub.nsi

@@ -1573,6 +1573,7 @@ Function LaunchApp
   ${If} $0 <> 0 ; integer comparison
     StrCpy $FirefoxLaunchCode "1"
     MessageBox MB_OK|MB_ICONQUESTION "$(WARN_MANUALLY_CLOSE_APP_LAUNCH)"
+    Call SendPing
     Return
   ${EndIf}
 !endif