Merge pull request #867 from trws/cd-fix

switched test to use -d for location check

share/spack/setup-env.sh

@@ -85,7 +85,7 @@ function spack {
                 command spack cd -h
             else
                 LOC="$(spack location $_sp_arg "$@")"
-		if [[ "x" -ne "x$LOC" ]] ; then
+                if [[ -d "$LOC" ]] ; then
                     cd "$LOC"
                 fi
             fi