Only display spacer row when necessary
Only display spacer row when necessary

If there are no existing branch mappings, the spacer row is useless

Fixes #244

make-all/source-integration,make-all/source-integration,mantisbt-plugins/source-integration,mantisbt-plugins/source-integration,dregad/source-integration,mantisbt-plugins/source-integration,make-all/source-integration,dregad/source-integration,dregad/source-integration