LU-1049 script: lc_net doesn't parse output correctly

LU-1049 script: lc_net doesn't parse output correctly

Port the second fix from bz=23234
The output of ping contains two ip addresses. The regex
matching picks up both addresses. The fix is to add
-m 1 to stop at the first match
Signed-off-by: Minh Diep <mdiep@whamcloud.com>
Change-Id: Iaefe42918b4587f88a8a0cb39cf9afb2a82021ba
Reviewed-on: http://review.whamcloud.com/2105
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: hongchao.zhang <hongchao.zhang@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>