Fix bug 1594 - Can not create Openstack vim due to special characters in username

I've checked the code in common and in NBI to see if there was a
possible vector for NoSQL Injection and there wasn't.

Change-Id: I9f1626f8d943999d94d82444aec12efa0f66ddc7
Signed-off-by: sousaedu <eduardo.sousa@canonical.com>