Extra tag is forgotten if loading module has a variant automatically set #484

$ module show foo/1.0
-------------------------------------------------------------------
/path/to/modulefiles/foo/1.0:

variant         --default val1 bar val1 val2 val3
-------------------------------------------------------------------
$ module load foo/1.0 --tag=keep-loaded
$ module list
Currently Loaded Modulefiles:
 1) foo/1.0{bar=val1}  

Key:
{variant=value}