fix libpam-lastlog2

this seems like a bug in the libpam-lastlog2 package

Author: mkocher

stemcell_builder/stages/password_policies/apply.sh

@@ -33,6 +33,15 @@ patch -p1 $chroot/etc/pam.d/common-auth < $assets_dir/ubuntu/common-auth.patch
 strip_trailing_whitespace_from $chroot/etc/pam.d/common-password
 patch -p1 $chroot/etc/pam.d/common-password < $assets_dir/ubuntu/common-password.patch
 
+# libpam-lastlog2 installs pam_lastlog2.so only to the multiarch path
+# (/usr/lib/x86_64-linux-gnu/security/) but PAM's securedir is /usr/lib/security/.
+# Bridge the gap so PAM can load the module referenced above.
+if [ -f "$chroot/usr/lib/x86_64-linux-gnu/security/pam_lastlog2.so" ] && \
+   [ ! -e "$chroot/usr/lib/security/pam_lastlog2.so" ]; then
+  ln -sf /usr/lib/x86_64-linux-gnu/security/pam_lastlog2.so \
+      "$chroot/usr/lib/security/pam_lastlog2.so"
+fi
+
 strip_trailing_whitespace_from $chroot/etc/pam.d/login
 patch $chroot/etc/pam.d/login < $assets_dir/ubuntu/login.patch