Fix ninja_clobber for Linux.
Fix ninja_clobber for Linux.

os.rmdir(path) sets e.errno to 39 on Linux.  Skip
this error when it happens.

TBR=stuartmorgan@chromium.org


Review URL: https://chromiumcodereview.appspot.com/10868099

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@153436 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build