postgresql: make sure pam conf installed when pam enabled

Update the pam check logic to make sure pam conf installed.

Before the patch:
root@intel-x86-64:~# rpm -ql postgresql | grep pam.d | grep postgresql
root@intel-x86-64:~#

After the patch:
root@intel-x86-64:~# rpm -ql postgresql | grep pam.d | grep postgresql
/etc/pam.d/postgresql
root@intel-x86-64:~#

Signed-off-by: Mingli Yu <mingli.yu@windriver.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
(cherry picked from commit a755af4fb5)
Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-oe/recipes-dbs/postgresql/postgresql.inc

@@ -205,7 +205,7 @@ do_install:append() {
     # multiple server config directory
     install -d -m 700 ${D}${sysconfdir}/default/${BPN}
 
-    if [ "${@d.getVar('enable_pam')}" = "pam" ]; then
+    if ${@bb.utils.contains('DISTRO_FEATURES', 'pam', 'true', 'false', d)}; then
         install -d ${D}${sysconfdir}/pam.d
         install -m 644 ${WORKDIR}/postgresql.pam ${D}${sysconfdir}/pam.d/postgresql
     fi