Remove cygwin disease from grit (python) invocations :)

build/grit_action.gypi

Index: build/grit_action.gypi
diff --git a/build/grit_action.gypi b/build/grit_action.gypi
index 9d078b453c2b0c7d59d5b33260ca25d028f1aeca..818c33be6426946fcba75136ff56bc8399fed37b 100644
--- a/build/grit_action.gypi
+++ b/build/grit_action.gypi
@@ -25,8 +25,11 @@
   ],
   'action': ['<@(grit_cmd)',
              '-i', '<(grit_grd_file)', 'build',
-             '-f', 'GRIT_DIR/../gritsettings/resource_ids',
+             # Combine the -f with the path to avoid gyp reinterpreting the path
+             # in terms of msvs' path structure.
+             '-fGRIT_DIR/../gritsettings/resource_ids',
              '-o', '<(grit_out_dir)',
              '<@(grit_defines)' ],
+  'msvs_cygwin_shell': 0,
   'message': 'Generating resources from <(grit_grd_file)',
 }