ST_AsMVT is being tested even on system without proto-buf installed

[robe]

berrie is failing. She doesn't have protobuf installed and evidentally someones snuck somes tests in tickets that require protobuf

-#4399|ST_AsMVTGeom|011100000001000000040000000000000000000000000000000000B0400000000000000000000000000000AF400000000000006040000000000000AF400000000000000000000000000000B040
08:17:24 -#4399|ST_AsMVTGeom|011100000001000000040000000000000000000000000000000000B0400000000000000000000000000000AF400000000000006040000000000000AF400000000000000000000000000000B040
08:17:24 -#4399|ST_AsMVTGeom|
08:17:24 -#4399|ST_AsGeoJSON|{"type":"Polygon","coordinates":[[[0,0],[1,1],[0,1],[0,0]]]}
08:17:24 -#4399|ST_AsGeoJSON|{"type":"GeometryCollection","geometries":[{"type":"Polygon","coordinates":[[[0,0],[1,1],[0,1],[0,0]]]}]}
08:17:24 -#4399|ST_AsGeoJSON|{"type":"Polygon","coordinates":[[]]}
08:17:24 +ERROR:  ST_AsGeobuf: Missing libprotobuf-c >= version 1.1
08:17:24 -----------------------------------------------------------------------------
08:17:15  tickets .. failed (diff expected obtained: /tmp/pgis_reg/test_102_diff)
08:17:24 -----------------------------------------------------------------------------
08:17:24 --- tickets_expected	2019-08-07 05:02:54.592281192 -0700
08:17:24 +++ /tmp/pgis_reg/test_102_out	2019-08-07 05:17:24.047138766 -0700
08:17:24 @@ -391,40 +391,4 @@
08:17:24  #4176|t
08:17:24  #4394
08:17:24  #4445|f|t|t|t|f|t|t|f|f|f|f|f|f|t|t

[robe]

In 17682:

Move protobuf specific ticket lines to mvt test
Closes #4472