HPCC-10563 Ignore blank plugin versions (generated from stubs)

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #5229 from ghalliday/issue10563

HPCC-10563 Ignore blank plugin versions (generated from stubs)

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>