Some fixes for supporting python3

* Fix imports.
* Use python3 syntax.
* Wrap map() calls with list().
* Use list() only wherever needed.
  (Thanks Conley!)
* Fix dictionary iteration methods
  (s/iteritems/items/).
* Make use of sorted() in appropriate places
* Use iterators directly in the loop.
* Don't use .keys() wherever it isn't needed.
* Use sys.maxsize instead of sys.maxint

TODO:
* Make repo work fully with python3. :)

Some of this was done by the '2to3' tool [1], by
applying the needed fixes in a way that doesn't
break compatibility with python2.

Links:
[1]: http://docs.python.org/2/library/2to3.html

Change-Id: Ibdf3bf9a530d716db905733cb9bfef83a48820f7
Signed-off-by: Chirayu Desai <cdesai@cyanogenmod.org>

git_refs.py

@@ -66,7 +66,7 @@ class GitRefs(object):
   def _NeedUpdate(self):
     Trace(': scan refs %s', self._gitdir)
 
-    for name, mtime in self._mtime.iteritems():
+    for name, mtime in self._mtime.items():
       try:
         if mtime != os.path.getmtime(os.path.join(self._gitdir, name)):
           return True
@@ -89,7 +89,7 @@ class GitRefs(object):
     attempts = 0
     while scan and attempts < 5:
       scan_next = {}
-      for name, dest in scan.iteritems():
+      for name, dest in scan.items():
         if dest in self._phyref:
           self._phyref[name] = self._phyref[dest]
         else:
@@ -108,6 +108,7 @@ class GitRefs(object):
       return
     try:
       for line in fd:
+        line = str(line)
         if line[0] == '#':
           continue
         if line[0] == '^':
@@ -150,6 +151,10 @@ class GitRefs(object):
     finally:
       fd.close()
 
+    try:
+      ref_id = ref_id.decode()
+    except AttributeError:
+      pass
     if not ref_id:
       return
     ref_id = ref_id[:-1]