Replace all os.remove calls

os.remove raises an exception when deleting read-only files on
Windows. Replace all calls with calls to platform_utils.remove,
which deals with deals with that issue.

Change-Id: I4dc9e0c9a36b4238880520c69f5075eca40f3e66
diff --git a/subcmds/sync.py b/subcmds/sync.py
index 93fea23..cda47fd 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -489,7 +489,7 @@
     for root, dirs, files in os.walk(path):
       for f in files:
         try:
-          os.remove(os.path.join(root, f))
+          platform_utils.remove(os.path.join(root, f))
         except OSError:
           print('Failed to remove %s' % os.path.join(root, f), file=sys.stderr)
           failed = True
@@ -500,7 +500,7 @@
     for d in reversed(dirs_to_remove):
       if platform_utils.islink(d):
         try:
-          os.remove(d)
+          platform_utils.remove(d)
         except OSError:
           print('Failed to remove %s' % os.path.join(root, d), file=sys.stderr)
           failed = True
@@ -712,7 +712,7 @@
     else:  # Not smart sync or smart tag mode
       if os.path.isfile(smart_sync_manifest_path):
         try:
-          os.remove(smart_sync_manifest_path)
+          platform_utils.remove(smart_sync_manifest_path)
         except OSError as e:
           print('error: failed to remove existing smart sync override manifest: %s' %
                 e, file=sys.stderr)
@@ -956,7 +956,7 @@
           f.close()
       except (IOError, ValueError):
         try:
-          os.remove(self._path)
+          platform_utils.remove(self._path)
         except OSError:
           pass
         self._times = {}
@@ -980,7 +980,7 @@
         f.close()
     except (IOError, TypeError):
       try:
-        os.remove(self._path)
+        platform_utils.remove(self._path)
       except OSError:
         pass