fix typo

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@43949 15284696-431f-4ddb-bdfa-cd5b030d7da7

scripts/g.extension/g.extension.py

@@ -74,7 +74,7 @@
 #%end
 #%flag
 #% key: d
-#% description: Don't deleted downloaded source code when installing new extension
+#% description: Don't delete downloaded source code when installing new extension
 #%end
 
 import os