tests: introduce PATCHEW_TEST_DATA_DIR in env
tests: introduce PATCHEW_TEST_DATA_DIR in env

This will be the tmp dir we create for the server data.

Signed-off-by: Fam Zheng <df9fd617995bad07eac70e27aa3fe5069270e3bd@redhat.com>

pvital/patchew,pvital/patchew,pvital/patchew,pvital/patchew