Use keystone[ldap] for ldap packages

Keystone now provides an "ldap" in extras to install its ldap
dependencies so devstack doesn't have to track the python
dependencies itself.

Installation of the extras is done in an extra install line. This is
slightly redundant, however this pattern works much better from an
install stand point as it supports an arbitrarily large number of
extras.

Partial-Bug: 1479962
Change-Id: If0f0ff48f3d6b3c414f2d6fcd747ecf45a397658

lib/keystone

@@ -506,6 +506,11 @@ function install_keystone {
     fi
     git_clone $KEYSTONE_REPO $KEYSTONE_DIR $KEYSTONE_BRANCH
     setup_develop $KEYSTONE_DIR
+
+    if is_service_enabled ldap; then
+        setup_develop $KEYSTONE_DIR ldap
+    fi
+
     if [ "$KEYSTONE_USE_MOD_WSGI" == "True" ]; then
         install_apache_wsgi
         if is_ssl_enabled_service "key"; then

lib/ldap

@@ -145,8 +145,6 @@ function install_ldap {
         sudo ldapadd -Y EXTERNAL -H ldapi:/// -f /etc/openldap/schema/inetorgperson.ldif
     fi
 
-    pip_install_gr ldappool
-
     rm -rf $tmp_ldap_dir
 }