minor fix for pragmahandler seg fault

Signed-off-by: Alex McCaskey <mccaskeyaj@ornl.gov>

compiler/clang/qcor-driver.in.cpp

@@ -66,6 +66,9 @@ protected:
 
     ParseAST(CI.getSema());
 
+    for (auto& p : pragmaHandlers) {
+        CI.getSema().getPreprocessor().RemovePragmaHandler(p.get());
+    }
     CI.getDiagnosticClient().EndSourceFile();
 
     std::string outName(fileName);