Fix pylint issue in payload.py

    ************* Module update_payload.payload
    W: 12, 0: Relative import 'applier', should be 'update_payload.applier' (relative-import)
    W: 13, 0: Relative import 'block_tracer', should be 'update_payload.block_tracer' (relative-import)
    W: 14, 0: Relative import 'checker', should be 'update_payload.checker' (relative-import)
    W: 15, 0: Relative import 'common', should be 'update_payload.common' (relative-import)
    W: 16, 0: Relative import 'error', should be 'update_payload.error' (relative-import)
    W: 17, 0: Relative import 'update_metadata_pb2', should be 'update_payload.update_metadata_pb2' (relative-import)
    C:222, 4: Missing function docstring (missing-docstring)
    E:261,33: Instance of 'DeltaArchiveManifest' has no 'partitions' member (no-member)

Test: repo upload
Change-Id: Ib3e99c6a3a5ea4575b442e672a871adc7b985289
diff --git a/scripts/update_payload/payload.py b/scripts/update_payload/payload.py
index f76c0de..d1a99ec 100644
--- a/scripts/update_payload/payload.py
+++ b/scripts/update_payload/payload.py
@@ -9,12 +9,12 @@
 import hashlib
 import struct
 
-import applier
-import block_tracer
-import checker
-import common
-from error import PayloadError
-import update_metadata_pb2
+from update_payload import applier
+from update_payload import block_tracer
+from update_payload import checker
+from update_payload import common
+from update_payload.error import PayloadError
+from update_payload import update_metadata_pb2
 
 
 #
@@ -215,6 +215,7 @@
   def Describe(self):
     """Emits the payload embedded description data to standard output."""
     def _DescribeImageInfo(description, image_info):
+      """Display info about the image."""
       def _DisplayIndentedValue(name, value):
         print('  {:<14} {}'.format(name+':', value))