landmine to clobber old GYP build artifacts to enable moving to GN.

BUG=chromium:652188
TBR=fbarchard@chromium.org

Review URL: https://codereview.chromium.org/2427643003 .

tools/get_landmines.py

@@ -38,6 +38,7 @@ def print_landmines():
   # landmine.
   # See the Chromium version in src/build/get_landmines.py for usage examples.
   print 'Clobber to remove GYP artifacts after switching bots to GN.'
+  print 'Another try to remove GYP artifacts after switching bots to GN.'
 
 
 def main():