remove wildcards from make spack core and packages

- This removes all wildcard imports EXCEPT `from spack import *` in packages

var/spack/repos/builtin/packages/r/package.py

@@ -22,10 +22,8 @@
 # License along with this program; if not, write to the Free Software
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-
-from spack import *
-from spack.util.environment import *
 import shutil
+from spack import *
 
 
 class R(AutotoolsPackage):