shared/api: Add omitempty to context
shared/api: Add omitempty to context

Signed-off-by: Thomas Hipp <5f82c492b3b00e427412d216ce820707a10c51ce@canonical.com>

stgraber/lxd,Skarlso/lxd,Skarlso/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,Skarlso/lxd,atxwebs/lxd,lxc/lxd,erikmack/lxd,erikmack/lxd,hallyn/lxd,mjeanson/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,atxwebs/lxd,hallyn/lxd,hallyn/lxd,Skarlso/lxd,erikmack/lxd,stgraber/lxd,hallyn/lxd,lxc/lxd,mjeanson/lxd,lxc/lxd,lxc/lxd,mjeanson/lxd,atxwebs/lxd,stgraber/lxd,atxwebs/lxd