Add non-zero exit code.

scripts/chip-job-save-result

@@ -3,6 +3,7 @@ import chipathlon.db
 import argparse
 import yaml
 import os
+import sys
 
 parser = argparse.ArgumentParser(description="Insert a bed file into the database.")
 parser.add_argument("-u", "--username", dest="username", help="Database username (if required).")
@@ -30,4 +31,5 @@ if os.path.isfile(args.file) and os.path.isfile(args.meta) and os.path.getsize(a
     print msg
 
 else:
-    print "Either input file %s or meta file %s does not exist." % (args.file, args.meta)
+    print "Either input file '%s' or meta file '%s' does not exist, or has zero size." % (args.file, args.meta)
+    sys.exit(1)