Drop unnecessary interfaces

It appears we don't need to use the account-control and
kernel-module-control interfaces.

* account-control: This is no longer needed, possibly because we've patched
  the offending call via patches/drop-use-of-fchownat.patch.

* kernel-module-control: While we get a denial for sys_module, it doesn't
  appear to be adversely affecting anything while testing. For more details,
  see [1].

[1] https://forum.snapcraft.io/t/auto-connecting-the-nova-hypervisor-interfaces/1145/10

Change-Id: Ifa666d6070dbb746dcf6fa18cad1789ff237f38e

snapcraft.yaml

@@ -23,8 +23,6 @@ apps:
     command: snap-openstack nova-compute
     daemon: simple
     plugs:
-      - account-control
-      - kernel-module-control
       - network
       - network-bind
       - network-control
@@ -36,7 +34,6 @@ apps:
     command: snap-openstack nova-api-metadata
     daemon: simple
     plugs:
-      - account-control
       - network
       - network-bind
       - firewall-control
@@ -44,7 +41,6 @@ apps:
     command: snap-openstack neutron-openvswitch-agent
     daemon: simple
     plugs:
-      - account-control
       - network
       - network-bind
       - network-control
@@ -57,7 +53,6 @@ apps:
     command: snap-openstack neutron-l3-agent
     daemon: simple
     plugs:
-      - account-control
       - network
       - network-bind
       - network-control
@@ -70,8 +65,6 @@ apps:
     command: snap-openstack neutron-dhcp-agent
     daemon: simple
     plugs:
-      - account-control
-      - kernel-module-control
       - network
       - network-bind
       - network-control
@@ -83,7 +76,6 @@ apps:
     command: snap-openstack neutron-metadata-agent
     daemon: simple
     plugs:
-      - account-control
       - network
       - network-bind
       - network-control