LU-56 libcfs: export a few symbols from libcfs

LU-56 libcfs: export a few symbols from libcfs

Export cfs_trace_copyin_string and cfs_strncasecmp from libcfs,
These symbols will be used by LNet patches soon.

Signed-off-by: Liang Zhen <liang@whamcloud.com>
Change-Id: I8722adec822f9d90322a59ff71afff87a9062efd
Reviewed-on: http://review.whamcloud.com/2920
Tested-by: Hudson
Reviewed-by: Bobi Jam <bobijam@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>