Update hooks.rst for Ganeti 2.7

- The migrate instance hook now also executes on the primary node in
  the "pre" phase.
- Instance hooks now get full network information on each nic, if a
  nic's network is set.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

doc/hooks.rst

@@ -286,11 +286,18 @@ INSTANCE_NAME, INSTANCE_PRIMARY, INSTANCE_SECONDARY,
 INSTANCE_OS_TYPE, INSTANCE_DISK_TEMPLATE, INSTANCE_MEMORY,
 INSTANCE_DISK_SIZES, INSTANCE_VCPUS, INSTANCE_NIC_COUNT,
 INSTANCE_NICn_IP, INSTANCE_NICn_BRIDGE, INSTANCE_NICn_MAC,
+INSTANCE_NICn_NETWORK_SUBNET, INSTANCE_NICn_NETWORK_GATEWAY,
+INSTANCE_NICn_NETWORK_SUBNET6, INSTANCE_NICn_NETWORK_GATEWAY6,
+INSTANCE_NICn_NETWORK_MAC_PREFIX, INSTANCE_NICn_NETWORK_TYPE,
 INSTANCE_DISK_COUNT, INSTANCE_DISKn_SIZE, INSTANCE_DISKn_MODE.
 
 The INSTANCE_NICn_* and INSTANCE_DISKn_* variables represent the
 properties of the *n* -th NIC and disk, and are zero-indexed.
 
+The INSTANCE_NICn_NETWORK_* variables are only passed if a NIC's network
+parameter is set (that is if the NIC is associated to a network defined
+via ``gnt-network``)
+
 
 OP_INSTANCE_CREATE
 ++++++++++++++++++
@@ -383,7 +390,7 @@ and secondary before migration.
 
 :directory: instance-migrate
 :env. vars: MIGRATE_LIVE, MIGRATE_CLEANUP, OLD_PRIMARY, OLD_SECONDARY, NEW_PRIMARY, NEW_SECONDARY
-:pre-execution: master node, secondary node
+:pre-execution: master node, primary and secondary nodes
 :post-execution: master node, primary and secondary nodes