Convert pam_pwhistory config to pwhistory.conf

With libpam 1.5.3, pam_pwhistory added support to get configuration
options from pwhistory.conf similar to faillock and pwquality. This
converts the pam_pwhistory config options to pwhistory.conf to match
faillock and pwquality.

Tested:
Confirmed that the remember setting works correctly from pwhistory.conf.

Confirmed that an existing pwhistory remember setting gets converted to
pwhistory.conf, if needed.

Signed-off-by: Jason M. Bills <jason.m.bills@linux.intel.com>
Change-Id: I8ec0c8b60f02f0e5aa97b3254225e9a5488cdb54
diff --git a/meta-phosphor/recipes-extended/pam/libpam/pwhistory.conf b/meta-phosphor/recipes-extended/pam/libpam/pwhistory.conf
new file mode 100644
index 0000000..1515fae
--- /dev/null
+++ b/meta-phosphor/recipes-extended/pam/libpam/pwhistory.conf
@@ -0,0 +1,2 @@
+enforce_for_root
+remember=0