Valgrind: Stop parsing if file open failed

Reported by Coverity.

Change-Id: Ibf12c563cb2cab50183c62a4e51cdbe238d0127e
Reviewed-by: hjk <hjk@qt.io>

src/plugins/valgrind/callgrindengine.cpp

@@ -270,7 +270,10 @@ void CallgrindToolRunner::triggerParse()
     cleanupTempFile();
     {
         TemporaryFile dataFile("callgrind.out");
-        dataFile.open();
+        if (!dataFile.open()) {
+            showStatusMessage(tr("Failed opening temp file..."));
+            return;
+        }
         m_hostOutputFile = FilePath::fromString(dataFile.fileName());
     }