libevents git submodule error

[smahapatra1]

While executing: git submodule update --init
I got error for java/commons_logging, java/log4j and libunwind in git clone step.
I changed the repositories in .gitmodules to:
https://github.com/apache/commons-logging.git
https://github.com/apache/log4j.git
https://github.com/llvm-mirror/libunwind.git.

Now I get error in libunwind git clone: server does not allow for unadvertised object...

[smahapatra1]

I changed from llvm-mirror to https://github.com/dropbox/libunwind.git to get the object with correct checksum.

I have fixed a "load" syntax in examples/run_under/BUILD to:
load('//tools:build_rules/run_under.bzl', 'run_under_test'.

I have also done three changes to use 'depset' instead of 'set' in generate_cc.bzl and grpc_proto.bzl (with order="compile" changed to order="postorder").

Now I am getting error in proto_library of grpc_proto.bzl:
line 158 and 161: type 'NoneType' has no method label().

What should I change the 'proto_pkg.label()' to?