Fix: legacy: Support "crm_node --remove" with a node name for corosync plugin (bnc#805278)

The "crm_node --remove" command has changed to be used with a node name,
but it doesn't work correctly for corosync plugin. This commit fixes it.
Merge pull request #264 from gao-yan/crm-node-remove

Fix: legacy: Support "crm_node --remove" with a node name for corosync plugin (bnc#805278)