LU-9833 utils: resolve buffer over runs in lustre_rsync

Newer version of gcc will report of snprintf is used in an
incorrect way. For the case of the lustre_rsync application
many times two buffers of size PATH_MAX are being placed into
one buffer of the size PATH_MAX. This can easily lead to a
buffer overrun. This patch resolves those bugs.

Test-Parameters: trivial testlist=lustre-rsync-test

Change-Id: I035b4a3b1d9695a16822649c2165e492e9f2879d
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/30373
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>