Updated trillian.proto which removes trillian_log_api dependency.

Trillian removed the trillian_log_api dependency from the
trillian.proto. Thus, we can now remove this from our dependencies.
Also fixed up pylintrc to ignore linting the generate protobuf
and grpc files.

Test: atest --host avbtool_test
Test: atest --host libavb_host_unittest
Test: ./avbtool make_icp_from_vbmeta \
  --vbmeta_image_path vbmeta.img \
  --output ./vbmeta_icp.img \
  --version_incremental only_for_testing \
  --transparency_log_servers [REDACTED]:80 \
  --transparency_log_pub_keys transparency_key2.pub \
  --key ~/android/aosp-libavb/external/avb/test/data/testkey_rsa4096.pem \
  --manufacturer_key manufacturer_key_4096.rsa \
  --algorithm SHA256_RSA4096

Bug: 138779249
Change-Id: Ib1d45ca3c3cbdb7da01320a943be71eb69422ee6
diff --git a/pylintrc b/pylintrc
index 06fe841..7d6abe3 100644
--- a/pylintrc
+++ b/pylintrc
@@ -27,6 +27,7 @@
 # Add files or directories to the blacklist. They should be base names, not
 # paths.
 ignore=CVS,.svn,.git
+ignore-patterns=.*pb2\.py,.*pb2_grpc\.py
 
 # Pickle collected data for later comparisons.
 persistent=yes