Unchecked return value in QMakeProject

CID 21629: The QMakeProject::read result was ignored.
MetaMakefileGenerator::createMakefileGenerator will be called if the
project was read.

Change-Id: I9187c82efd1abedcaa8e394f1fdb0b7f35a2b1d7
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

qmake/generators/metamakefile.cpp

@@ -230,10 +230,8 @@ MakefileGenerator
         build_proj->setExtraVars(basevars);
         build_proj->setExtraConfigs(basecfgs);
 
-        build_proj->read(project->projectFile());
-
-        //done
-        return createMakefileGenerator(build_proj);
+        if (build_proj->read(project->projectFile()))
+            return createMakefileGenerator(build_proj);
     }
     return 0;
 }