Handle race condition in directory creation.

If we try to make a directory, but someone else creates the directory
at the same time as us, we don't need to raise that error to the user.
They asked for the directory to exist, and now it does. This fixes
the race condition which was causing that error to be raised, and
closes #1648.

lib/ansible/modules/files/file.py

@@ -18,6 +18,7 @@
 # You should have received a copy of the GNU General Public License
 # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
 
+import errno
 import shutil
 import stat
 import grp
@@ -280,7 +281,13 @@ def main():
                 if not os.path.isabs(path):
                     curpath = curpath.lstrip('/')
                 if not os.path.exists(curpath):
-                    os.mkdir(curpath)
+                    try:
+                        os.mkdir(curpath)
+                    except OSError, ex:
+                        # Possibly something else created the dir since the os.path.exists
+                        # check above. As long as it's a dir, we don't need to error out.
+                        if not (ex.errno == errno.EEXISTS and os.isdir(curpath)):
+                            raise
                     tmp_file_args = file_args.copy()
                     tmp_file_args['path']=curpath
                     changed = module.set_fs_attributes_if_different(tmp_file_args, changed)