LU-8311 mount: fix lmd_parse() to parse colon as NID delimiter

LU-8311 mount: fix lmd_parse() to parse colon as NID delimiter

In multi-rail and failover configurations, colon is a valid
delimiter in LNET nid list to separate different hosts.
This patch fixes lmd_parse()->lmd_parse_nidlist() to handle
both comma and colon as delimiters.

Signed-off-by: Jian Yu <jian.yu@intel.com>
Change-Id: I287e08c22c82c2143fe9aba185473a672e8f1429
Reviewed-on: http://review.whamcloud.com/21329
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>