Update xpath commands

Update xpath commands

'xpath' command in CentOS 8 uses the following format:

  xpath [options] -e query [-e query...] [filename...]

instead of this in CentOS 7:

  xpath [filename] query

Update the commands in the shell scripts to follow the new format with
the old one as a fallback to support both versions.

Change-Id: I4a99a7f18e69d2d1c4c67aca16a4a6ab57618cb2
Signed-off-by: Sangwook Ha <sangwook.ha@verizon.com>