process_error_message(): exit(0) should be exit(1)

Change-Id: Iae815c296b93146098e1d78878d7cd7e8de57f99
Signed-off-by: Michael Walsh <micwalsh@us.ibm.com>
diff --git a/lib/gen_valid.py b/lib/gen_valid.py
index c68555b..ad5de1f 100755
--- a/lib/gen_valid.py
+++ b/lib/gen_valid.py
@@ -106,7 +106,7 @@
 
     gp.print_error_report(error_message)
     if exit_on_error:
-        exit(0)
+        exit(1)
     return False