py: check existence before creating a new directory

If the name ends with '/', check if the tmp directory already exists
before trying to create it. Previously, it would result in an OSError
exception being thrown.

Signed-off-by: Andreas Tolfsen <[email protected]>

Author: cezarelnazli

Diff for: py/selenium/webdriver/firefox/firefox_profile.py

@@ -254,7 +254,7 @@ def _install_extension(self, addon, unpack=True):
             tmpdir = tempfile.mkdtemp(suffix='.' + os.path.split(addon)[-1])
             compressed_file = zipfile.ZipFile(addon, 'r')
             for name in compressed_file.namelist():
-                if name.endswith('/'):
+                if name.endswith('/') and not os.path.isdir(os.path.join(tmpdir, name)):
                     os.makedirs(os.path.join(tmpdir, name))
                 else:
                     if not os.path.isdir(os.path.dirname(os.path.join(tmpdir, name))):