updated start time and finish time for task status to be iso8601 datetim...

...e string instead of utc timestamp

https://bugzilla.redhat.com/show_bug.cgi?id=1067637

Sample output - 

Operations:  sync
Resources:   test-repo (repository)
State:       Successful
Start Time:  2014-02-26T18:40:23Z
Finish Time: 2014-02-26T18:40:31Z
Result:      
....