Squish: Throw fatal on empty task

Change-Id: I815810ffbe295cabf37e8a14000243481b799800
Reviewed-by: Robert Loehning <robert.loehning@digia.com>

tests/system/shared/build_utils.py

@@ -132,6 +132,8 @@ def createTasksFile(buildIssues):
             tData = "warning"
         else:
             tData = "unknown"
+        if fData.strip() == "" and lData == "-1" and dData.strip() == "":
+            test.fatal("Found empty task.")
         file.write("%s\t%s\t%s\t%s\n" % (fData, lData, tData, dData))
     file.close()
     test.log("Written tasks file %s" % outfile)