Add reserved param for v2.4

v2.4 added 'reserved' param to fixed ip output, this patch
added it into doc.

Change-Id: I3be65d6aa5e36662cbb09f408124d0abb8bbfdf5
Implements: blueprint api-ref-in-rst-ocata

api-ref/source/os-fixed-ips.inc

@@ -41,6 +41,7 @@ Response
   - cidr: cidr
   - host: fixed_ip_host
   - hostname: fixed_ip_hostname
+  - reserved: reserved_fixedip
 
 
 **Example Show Fixed Ip Details: JSON response**

api-ref/source/parameters.yaml

@@ -3623,6 +3623,13 @@ reserved:
   in: body
   required: true
   type: integer
+reserved_fixedip:
+  description: |
+    True if the fixed ip is reserved, otherwise False.
+  in: body
+  required: true
+  type: boolean
+  min_version: 2.4
 resetNetwork:
   description: |
     The action.