[fuel-plugin-ldap] hints to fill settings

[Kyrylo Romanenko]

Steps:
1. Deploy Fuel .
2. Install LDAP plugin.
3. Create a cluster by wizard: 1 Controller, 1 Compute, 1 Cinder, Neutron VLAN, Cinder LVM.
4. Enable "LDAP plugin for Keystone" in Settings.
Clear fields or fill with invalid data.

Actual hints:
Domain should match regex '^([a-zA-Z0-9._-]+)$'
LDAP URL should match regex 'ldap://([a-zA-Z0-9._-]+)(:[0-9]+)?$'
Password should match regex '^([a-zA-Z0-9_-]+)$'

Expected more user- friendly hints, usually shown at online services, something like this:
"Domain should look like mydomain.com"
"LDAP URL should be ldap://<server_ip>:<port>"
"Password must contain..."

VERSION:
  feature_groups:
    - mirantis
  production: "docker"
  release: "7.0"
  openstack_version: "2015.1.0-7.0"
  api: "1.0"
  build_number: "301"
  build_id: "301"
  nailgun_sha: "4162b0c15adb425b37608c787944d1983f543aa8"
  python-fuelclient_sha: "486bde57cda1badb68f915f66c61b544108606f3"
  fuel-agent_sha: "50e90af6e3d560e9085ff71d2950cfbcca91af67"
  fuel-nailgun-agent_sha: "d7027952870a35db8dc52f185bb1158cdd3d1ebd"
  astute_sha: "6c5b73f93e24cc781c809db9159927655ced5012"
  fuel-library_sha: "5d50055aeca1dd0dc53b43825dc4c8f7780be9dd"
  fuel-ostf_sha: "2cd967dccd66cfc3a0abd6af9f31e5b4d150a11c"
  fuelmain_sha: "a65d453215edb0284a2e4761be7a156bb5627677"

LDAP Plugin: build from 30th September.

[Max Yatsenko (myatsenko)]

This patch https://review.openstack.org/#/c/230360/ provide fields validation using regexp.
The patch was merged.