+++ This bug was initially created as a clone of Bug #1169707 +++

Description of problem:
`gluster peer probe hostname` fails when hostname contains '_'

Version-Release number of selected component (if applicable):
3.4.2-1

How reproducible:
always

Steps to Reproduce:
1.set a host'name to "n_***", such as "n_node";
2.on another node, execute `gluster peer probe n_node`
3.

Actual results:
2. 
n_node is an invalid address
Usage: peer probe <HOSTNAME>


Expected results:
2.
peer probe: success


Additional info:

--- Additional comment from Kaleb KEITHLEY on 2014-12-02 07:40:09 EST ---

RFC1035 indicates that only 0-9A-Za-z and '-' are legal characters in a hostname, however it was agreed during review that we should relax our hostname checking