i.landsat.rgb: fix global variable

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@52267 15284696-431f-4ddb-bdfa-cd5b030d7da7

scripts/i.landsat.rgb/i.landsat.rgb.py

@@ -123,6 +123,8 @@ def main():
     full = flags['f']
     preserve = flags['p']
     reset = flags['r']
+    
+    global do_mp
 
     if flags['s']:
         do_mp = False