Add optional silent install and config of ldap to devstack

Edited initial ldap entries and olcdb template file as recommended by Brant.

Change-Id: I1404cc5c754f878e32a2d10254840d092211e6e6
diff --git a/files/apts/ldap b/files/apts/ldap
new file mode 100644
index 0000000..81a00f2
--- /dev/null
+++ b/files/apts/ldap
@@ -0,0 +1,3 @@
+ldap-utils
+slapd # NOPRIME
+python-ldap