pam-passwdqc: fix the hardcoded libdir

Fix QA issue when enable multilib:
WARNING: QA Issue: pam-passwdqc-dbg: found library in wrong location:
/lib/security/.debug/pam_passwdqc.so
pam-passwdqc: found library in wrong location:
/lib/security/pam_passwdqc.so [libdir]

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>