pm-utils: fix multilib conflictions

It fails to instal pm-utils and lib32-pm-utils at same time:

Error: Transaction test error:
  file /usr/bin/pm-is-supported conflicts between attempted installs of lib32-pm-utils-1.4.1-r1.corei7_32 and pm-utils-1.4.1-r1.corei7_64
  file /usr/sbin/pm-hibernate conflicts between attempted installs of lib32-pm-utils-1.4.1-r1.corei7_32 and pm-utils-1.4.1-r1.corei7_64
  file /usr/sbin/pm-powersave conflicts between attempted installs of lib32-pm-utils-1.4.1-r1.corei7_32 and pm-utils-1.4.1-r1.corei7_64
  file /usr/sbin/pm-suspend conflicts between attempted installs of lib32-pm-utils-1.4.1-r1.corei7_32 and pm-utils-1.4.1-r1.corei7_64
  file /usr/sbin/pm-suspend-hybrid conflicts between attempted installs of lib32-pm-utils-1.4.1-r1.corei7_32 and pm-utils-1.4.1-r1.corei7_64

All of the conflicted files either is script which source a file in
${libdir}, or a link file to some file in ${libdir}. Compare the content
of installed files in ${libdir} exclude binaries, only the paths of
${libdir} diff. So re-define libdir with ${nonarch_libdir} to fix the
conflicts.

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit f836541b)
Signed-off-by: Steve Sakoman <steve@sakoman.com>