propertycacher: make parent directories

Change-Id: I4557ddab56f4cbea5b177e3b05ef28c367c6e602
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/obmc/dbuslib/propertycacher.py b/obmc/dbuslib/propertycacher.py
index 701a413..ce83195 100644
--- a/obmc/dbuslib/propertycacher.py
+++ b/obmc/dbuslib/propertycacher.py
@@ -29,8 +29,11 @@
 
 def save(obj_path, iface_name, properties):
     print "Caching: "+obj_path
+    filename = getCacheFilename(obj_path, iface_name)
+    parent = os.path.dirname(filename)
     try:
-        filename = getCacheFilename(obj_path, iface_name)
+        if not os.path.exists(parent):
+            os.makedirs(parent)
         output = open(filename, 'wb')
         try:
             ## use json module to convert dbus datatypes