Description of problem:
incorrect error message given for stopmigrate when no migration is occurring.

"Cannot stop remove bricks Gluster Brick(s). Invalid task type.]"


Version-Release number of selected component (if applicable):
rhsc-cb15

How reproducible:
100% of the time


Steps to Reproduce:
1. create a simple volume in rhsc
2. via rest call stopmigrate on the volume with some of the bricks
(example request)
POST /api/clusters/73db05ad-775a-405d-b4e9-91cf5dbb54e7/glustervolumes/81f47779-49ff-40d1-9dab-9de32ad390d7/bricks/stopmigrate
<action>[\n]"
    <bricks>[\n]"
        <replica_count>0</replica_count>[\n]"
        <brick>[\n]"
            <name>rhsc-cb15-node-a:/bricks/201401212251036201942637805</name>[\n]"
        </brick>[\n]"
    </bricks>[\n]"
</action>[\n]"

Actual results:
< "<?xml version="1.0" encoding="UTF-8" standalone="yes"?>[\n]"
< "<fault>[\n]"
< "    <reason>Operation Failed</reason>[\n]"
< "    <detail>[Cannot stop remove bricks Gluster Brick(s). Invalid task type.]</detail>[\n]"
< "</fault>[\n]"




Expected results:

Should be something similar to "Cannot stop remove bricks. Remove brick has not been started yet."

Additional info: