bump(net-misc/gsutil): Update dependencies for gsutil-3.31

Dependencies updated:
    dev-python/crcmod
    dev-python/httplib2
    dev-python/pyopenssl
    dev-python/python-gflags

Additionally, dev-cpp/gflags was also updated because it is a
spectacularly old version that conflicts with python-gflags.
Merge pull request #8 from marineam/gsutil

bump(net-misc/gsutil): Update dependencies for gsutil-3.31