Bug 1246264 - Ensure cache directory exists for artifacts installation r=chmanchester

--HG--
extra : commitid : Fz9TFGL0WgM

python/mozbuild/mozbuild/mach_commands.py

@@ -5,6 +5,7 @@
 from __future__ import absolute_import, print_function, unicode_literals
 
 import argparse
+import errno
 import itertools
 import json
 import logging
@@ -1481,6 +1482,12 @@ class PackageFrontend(MachCommandBase):
         state_dir = self._mach_context.state_dir
         cache_dir = os.path.join(state_dir, 'package-frontend')
 
+        try:
+            os.makedirs(cache_dir)
+        except OSError as e:
+            if e.errno != errno.EEXIST:
+                raise
+
         import which
         if self._is_windows():
           hg = which.which('hg.exe')