Changed the name of the timeout macro in riakc.hrl

Change the timeout macro name to DEFAULT_PB_TIMEOUT.

The name DEFAULT_TIMEOUT is confusing, because the riak-erlang-client and riak-erlang-http-client packages use riakc.hrl . Adding PB to the macro name makes it clear to the user they are changing the default timeout for the protobuf client and not http.

In the future, it may make sense to split out common functionality, including macros, specs and records, to a common riak-erlang-client-common project. It doesn't smell right that the http client can see the protobuf client's timeout macro.