LU-797 tests: skip ost-pools.sh 23b when SLOW=no

LU-797 tests: skip ost-pools.sh 23b when SLOW=no

Running test_23b can take over 30 minutes, and should not be run on a
large LUN inside a VM.  Print out some of the constants that determine
whether the test is run or not, for debugging purposes.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I7491002276e36994be4baf30a731576c8ced7530
Reviewed-on: http://review.whamcloud.com/2091
Tested-by: Hudson
Reviewed-by: Johann Lombardi <johann@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>