Fix client.crt issue when it is a broken symlink (SOFTWARE-2455)
Fix client.crt issue when it is a broken symlink (SOFTWARE-2455)

When ~/.osg-koji/client.crt is a broken symlink (e.g. to a grid cert that doesn't exist yet), `osg-koji setup` is fooled into thinking the file doesn't exist and goes down the wrong code path. Fix this.

matyasselmeci/osg-build,opensciencegrid/osg-build,matyasselmeci/osg-build,opensciencegrid/osg-build