remove GT source installer directory after each build because we're running out of disk space
remove GT source installer directory after each build because we're running out of disk space

ellert/globus-toolkit,ellert/globus-toolkit,globus/globus-toolkit,ellert/globus-toolkit,ellert/globus-toolkit,ellert/globus-toolkit,gridcf/gct,gridcf/gct,globus/globus-toolkit,globus/globus-toolkit,globus/globus-toolkit,gridcf/gct,ellert/globus-toolkit,globus/globus-toolkit,globus/globus-toolkit,gridcf/gct,gridcf/gct,ellert/globus-toolkit,gridcf/gct,globus/globus-toolkit,ellert/globus-toolkit,globus/globus-toolkit