Description of problem:
Adding the "--xml" flag to geo-replication commands does not yield useful info.  

This seems to be a bug and a doc error.  For example, this is maddening with "status detail" because the xml return is bogus, but for "start" it seems correctish but unclear.

Note that some fields are difficult to parse in plain sting format (status detail being the leader, and most in need of parsing/ingest into other systems)

Version-Release number of selected component (if applicable):
3.5.2

How reproducible:
Always

Steps to Reproduce:
1. setup geo-replication
2. gluster --xml volume geo-replication SVOL THOST::TVOL status detail

Actual results:
get back XML that may or may not reflect actual data, but unable to verify.

Expected results:
Get useful XML corresponding to the data out woudl get in non-xml mode.


Additional info:
# here's a sucessful start
root@sm-dev-floor:~ # gluster --xml volume geo-replication test-floor sm-dev-sky::test-floor-replica start
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<cliOutput>
  <opRet>0</opRet>
  <opErrno>9</opErrno>
  <opErrstr/>
  <geoRep>
    <type>1</type>
    <master>test-floor</master>
    <slave>sm-dev-sky::test-floor-replica</slave>
  </geoRep>
</cliOutput>
root@sm-dev-floor:~ #

# here is "status detail" ; note that without the --xml flag, the output looks correct and has much more data.
root@sm-dev-sky:~ # gluster --xml volume geo-replication test-more-replica sm-dev-floor::test-more-replica status detail
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<cliOutput>
  <opRet>0</opRet>
  <opErrno>0</opErrno>
  <opErrstr/>
  <geoRep>
    <type>4</type>
  </geoRep>
</cliOutput>
root@sm-dev-sky:~ #