THRIFT-2450:include HowToContribute in the src repo
Client: build
Patch: jfarrell

Renamed doc files.
diff --git a/doc/HowToCommit.md b/doc/committers.md
similarity index 100%
rename from doc/HowToCommit.md
rename to doc/committers.md
diff --git a/doc/HowToContribute.md b/doc/contributing.md
similarity index 100%
rename from doc/HowToContribute.md
rename to doc/contributing.md