Description of problem: 
When reset remote access(or reset password), the vmaccess.py do twice sshd_config backup executions:
1. Backup sshd_config then set "ChallengeResponseAuthentication no" in the sshd_config
2. Backup sshd_config then put a default sshd_config file into the VM
So there should be 2 backup files(named like sshd_config_2016-11-02T06:17:05Z) in the /etc/ssh/ folder. But there's only one backup file. Because the backup file name use the time string, and the twice backup execution are too close(in 1 second) that the time strings are the same, so the second backup file covers the first backup file.

Version-Release number of selected component (if applicable): 
VMAccess-1.4.6.0
WALinuxAgent-2.2.0(Isn't about WALA)

RHEL Version: RHEL-7.3

How reproducible: 
100% 

Steps to Reproduce: 
1. Prepare a VM. Modify the value in the /etc/ssh/sshd_config, set "ChallengeResponseAuthentication yes".
2. Run "reset remote access" from Azure portal.
3. Check the "ChallengeResponseAuthentication" item inside the sshd_config_* file

Actual Result: 
The "ChallengeResponseAuthentication" is "no" inside the backup sshd_config_* file

Expect Result: 
The "ChallengeResponseAuthentication" is "yes" inside the backup sshd_config_* file

Additional Info: 
None