Add a utility function to get command of an incident
Add a utility function to get command of an incident

Incidents may request live repairs on a node. In this case,
they are expected to also provide a command field in the incident
description. Add a utility function to extract it, if present.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Petr Pudlak <9d19625f8ee825a2c398462ed335cbcf98f79c32@google.com>

leshchevds/ganeti,andir/ganeti,andir/ganeti,mbakke/ganeti,onponomarev/ganeti,leshchevds/ganeti,onponomarev/ganeti,leshchevds/ganeti,mbakke/ganeti,ganeti/ganeti,ganeti/ganeti,andir/ganeti,mbakke/ganeti,ganeti/ganeti