Bug 1412756 - Do not throw exceptions when the 'Crash Reports/pending' directory is missing; r=mconley

MozReview-Commit-ID: 2tFfgiGeGSl

--HG--
extra : rebase_source : da4ba2d33986fb5d90ad50d0792ca735dcb45c81

toolkit/crashreporter/CrashSubmit.jsm

@@ -491,14 +491,14 @@ this.CrashSubmit = {
     try {
       dirIter = new OS.File.DirectoryIterator(pendingDir);
     } catch (ex) {
-      if (ex.becauseNoSuchFile) {
-        return ids;
-      }
-
       Cu.reportError(ex);
       throw ex;
     }
 
+    if (!(await dirIter.exists())) {
+      return ids;
+    }
+
     try {
       let entries = Object.create(null);
       let ignored = Object.create(null);