A dependency on 'com.jcraft.jzlib' was added in JGit [1], so add that
to the dependencies for building JGit from source.
Also move the 'hamcrest-library' dependency out of WORKSPACE into the
jgit rules where it will be added conditionally.
Depends on [2] which harmonizes JGit's dependency names to align with
the names used in Gerrit since change I1e75690fe. Without [2], the
build will fail with errors like:
"no such package '@commons_compress//jar'"
[1] https://git.eclipse.org/r/#/c/114907/
[2] https://git.eclipse.org/r/#/c/128348/
Change-Id: I33be13e7f36ec2bcacbb9eb0983c88c6f3082097
125406c641