Changes to address failures in max_vm_flows and rsyslog.

This is a combination of 3 commits. Commit IDs:
3082041
c1b016e
158aed6

The first commit's message is:

1. Change in max_vm_flows.
    a. calling nova_fixture.wait_till_vm_is_up() to make sure vm
       is up before pinging its interface.

2. Changes in rsyslog.
    a. using copy_file_to_server in place of fab_put_file_to_vm
       to copy files to compute nodes.
    b. if there is no collector less compute exit gracefully.

Change-Id: I514235b680ae3d3ec6d0f7713f698847f999ad75

The 2nd commit message is:

1. Using node specific username and password instead of username/
password from inputs.
2. Replacing wait_till_vm_is_up() from nova_fixture with same
routine from vm_fixture.

Change-Id: I514235b680ae3d3ec6d0f7713f698847f999ad75

This is the 3rd commit message:

Fixing syntax error.
Unmatched [] were causing errors in test discovery,
resulting in review - jenkins job failure.

Change-Id: I514235b680ae3d3ec6d0f7713f698847f999ad75
Merge "Changes to address failures in max_vm_flows and rsyslog." into R2.0