Remove gpsnap

* Remove a previously deprecated utility
* Remove mentions of gpsnap
Signed-off-by: NMarbin Tan <mtan@pivotal.io>

gpAux/releng/NON_PRODUCTION_FILES.txt

@@ -12,7 +12,6 @@ bin/gprecoverseg.py
 bin/gptorment.pl
 bin/gpugcluster
 bin/lib/gpgetconfig.py
-bin/lib/gpsnap.py
 bin/lib/gptest.py
 bin/pgbench
 bin/postgresql_conf_gp_additions

gpAux/releng/QAUTILS_FILES.txt

@@ -4,7 +4,6 @@ bin/gpdebug
 bin/gpfaultinjector
 bin/gptorment.pl
 bin/lib/gpgetconfig.py
-bin/lib/gpsnap.py
 bin/pgbench
 bin/run_operator_tests.pl
 lib/python/gppylib/programs/clsInjectFault.py