gradle: Trim default value if string
gradle: Trim default value if string

For consistency with the bndUnprocessed method, we also trim the supplied
defaultValue, if it is a string.

Signed-off-by: BJ Hargrave <3d26bb3930946e3370762d769a073cece444c2d8@bjhargrave.com>

mcculls/bnd,joansmith/bnd,psoreide/bnd,magnet/bnd,psoreide/bnd,xtracoder/bnd,magnet/bnd,psoreide/bnd,lostiniceland/bnd,mcculls/bnd,lostiniceland/bnd,mcculls/bnd,lostiniceland/bnd,GEBIT/bnd,magnet/bnd,xtracoder/bnd,joansmith/bnd,GEBIT/bnd