LU-10825 libcfs: generate ip addresses

LU-10825 libcfs: generate ip addresses

Add infrastructure API cfs_ip_addr_range_gen() to generate a
maximum of 'count' IP addresses from an expression.

Test-Parameters: trivial
Signed-off-by: Amir Shehata <amir.shehata@intel.com>
Change-Id: I479dd7128eef404106a7863124a38c501150ba9e
Reviewed-on: https://review.whamcloud.com/31785
Reviewed-by: Sonia Sharma <sonia.sharma@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>