Changed test for renew slice to only attempt to renew for 8 hours instead of 12 to be consistent with slice expiration on gpolab.  Small change to default slicename.
Changed test for renew slice to only attempt to renew for 8 hours instead of 12 to be consistent with slice expiration on gpolab.  Small change to default slicename.

GENI-NSF/gram,tcmitchell/geni-tools,GENI-NSF/gram,GENI-NSF/gram,tcmitchell/geni-tools,plantigrade/geni-tools,ahelsing/geni-tools,ahelsing/geni-tools,plantigrade/geni-tools