variant of strprintf() which accepts va_list as parameter instead of variable args (...) Change-Id: I205acf3aaf5440890d5f9cad693c6a358a5d9218 BUG: 1089216 Signed-off-by: Anand Avati <avati@redhat.com> Reviewed-on: http://review.gluster.org/7539 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>