Fix pylint warnings in update_device.py

We weren't actually using our own pylintrc file in repo upload hook,
which will be fixed by https://android-review.googlesource.com/#/c/platform/tools/repohooks/+/458996/

Even though both camel case and snake case are allowed for function
and method names, they still have to be consistent in a single file.
https://pylint.readthedocs.io/en/latest/user_guide/options.html#multiple-naming-styles

Bug: 27316596
Test: repo upload
Change-Id: I98adba957a547115ef3d8b00fe2e3e4931707b31
diff --git a/scripts/update_device.py b/scripts/update_device.py
index 75c58a7..63d0fc9 100755
--- a/scripts/update_device.py
+++ b/scripts/update_device.py
@@ -93,7 +93,7 @@
   """
 
   @staticmethod
-  def _ParseRange(range_str, file_size):
+  def _parse_range(range_str, file_size):
     """Parse an HTTP range string.
 
     Args:
@@ -141,11 +141,11 @@
       self.send_response(200)
 
     stat = os.fstat(f.fileno())
-    start_range, end_range = self._ParseRange(self.headers.get('range'),
-                                              stat.st_size)
+    start_range, end_range = self._parse_range(self.headers.get('range'),
+                                               stat.st_size)
     logging.info('Serving request for %s from %s [%d, %d) length: %d',
-             self.path, self.serving_payload, start_range, end_range,
-             end_range - start_range)
+                 self.path, self.serving_payload, start_range, end_range,
+                 end_range - start_range)
 
     self.send_header('Accept-Ranges', 'bytes')
     self.send_header('Content-Range',