Description of problem:

 Glusterfs returns the same error code for different errors in create volume CLI

Version-Release number of selected component (if applicable):


How reproducible:

Always
Steps to Reproduce:
1. Create a volume with bricks from root partition without using force option
2. Create a volume with invalid brick directory

Actual results:
  
  For both the cases glusterfs returns the same error code.

 For 1:

 <cliOutput>
  <opRet>-1</opRet>
  <opErrno>2</opErrno>
  <opErrstr>The brick 10.70.43.87:/bricks/v11-1 is is being created in the root partition. It is recommended that you don't use the system's root partition for storage backend. Or use 'force' at the end of the command if you want to override this behavior.</opErrstr>
</cliOutput>

For 2:

<cliOutput>
  <opRet>-1</opRet>
  <opErrno>2</opErrno>
  <opErrstr>Failed to create brick directory for brick 10.70.43.87:/brickkks/v11-1. Reason : No such file or directory </opErrstr>
</cliOutput>

  In both the cases same error code is returned though the error message is different.

Expected results:

  Glusterfs should returns different error code for different errors.

Additional info:
  Returning different error codes helps in handling the error in UI.