bug #3334: skip non defined objects when searching for vcenter templates

Some objects returned by childEntity can be already deletend when they are accessed.
This patch skips these objects.

(cherry picked from commit e2886255464e666c6a62d91cc1d016da6ab1a643)
feature #3327: search recursively for objects in vcenter

It searches for both hosts and vms inside folders.

Based on the patch sent by Jens Grunert:

https://github.com/OpenNebula/one/pull/39
(cherry picked from commit 4d90449753b6275199cc120806aa9e028b08e3a5)
Bug #3256: Change RMDelete return code
bug #3303: Do not ask for password for ldap user creation
bug #3293: move vcenter_driver.rb to /usr/lib/one/ruby
Feature #3305: Enable context in vCenter view

(cherry picked from commit 4c277b87e439ce7215666234980fb95e7cb1561a)
Solve recursion problem in vCenter driver for hierarchy function

(cherry picked from commit ab35b92babe0383fd193866171f75084a1e07f31)
bug #3304: Add support for different time formats in acct inputs
bug #3304: Fix acct end_time placeholder
Bug #3332: Attach non-persistent disks does not work for ceph
Bug #3353: Do not set last_pool time to 0 in lcm::monitor_poweron
bug #3276: Check client errors when creating a new support request
bug #3315: use semantic versioning for remotes

onehost sync was using alphabetical comparison but this method does not work for this
comparison:

4.10.0 > 4.8.0

Now the versions are parsed by Gem::Version, that comes with rubygems and should
be installed in the frontend.

When the version can not be parsed it falls back to text comparison or forces update
if the comparison can not be made (one of the two versions is malformed).

More information about semantic versioning: http://semver.org/
bug #3276: Remove debug info
Bug #3352: Fix refresh in VM attach disk/nic
Bug #3275: Fix cluster wizard columns
bug #3359: Fix cep pool name tooltip
bug #3359: Fix gluster_volume assignment
Bug #3359: Add missing ceph attrs
Bug #3350: Remove cluster -1 from the acl wizard