migrate_from action test is missing OCF_RESKEY_CRM_meta_migrate_source environment variable

When testing migrate_to command, the environment variable OCF_RESKEY_CRM_meta_migrate_target must be passed to let agent know about the target node.

Please see http://www.linux-ha.org/doc/dev-guides/_literal_migrate_from_literal_action.html

Start by locating the test for the migrate_to command and compare its environment setup with the migrate_from action described in the linked Linux-HA guide. Update the migrate_from test so OCF_RESKEY_CRM_meta_migrate_source is passed, then run the relevant action tests and confirm the agent receives the source node.

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