Avoid nova-manage floating create <IP addr>/32

Fixes bug 951161

Avoid the counter-intuitive use of the /32 range to indicate a specific
individial IP address.

Instead a floating IP for a specific individual address is created by
dropping the range specifier altogether, e.g.:

  nova-manage floating create 192.168.1.150

Change-Id: I54b124e961accefa47f6faa7f201809c545c3fa5

bin/nova-manage

@@ -624,18 +624,17 @@ class FloatingIpCommands(object):
     """Class for managing floating ip."""
 
     @staticmethod
-    def network_to_host_list(network):
-        """Return the list of host of a network.
-
-        If the network is empty and only has one host, then we consider it
-        has the host in the network.
+    def address_to_hosts(addresses):
         """
+        Iterate over hosts within a address range.
 
-        if network.size == 1:
-            yield network.ip
-        else:
-            for host in network.iter_hosts():
-                yield host
+        If an explicit range specifier is missing, the parameter is
+        interpreted as a specific individual address.
+        """
+        try:
+            return [netaddr.IPAddress(addresses)]
+        except ValueError:
+            return netaddr.IPNetwork(addresses).iter_hosts()
 
     @args('--ip_range', dest="ip_range", metavar='<range>', help='IP range')
     @args('--pool', dest="pool", metavar='<pool>', help='Optional pool')
@@ -643,13 +642,12 @@ class FloatingIpCommands(object):
           help='Optional interface')
     def create(self, ip_range, pool=None, interface=None):
         """Creates floating ips for zone by range"""
-        addresses = netaddr.IPNetwork(ip_range)
         admin_context = context.get_admin_context()
         if not pool:
             pool = FLAGS.default_floating_pool
         if not interface:
             interface = FLAGS.public_interface
-        for address in self.network_to_host_list(addresses):
+        for address in self.address_to_hosts(ip_range):
             db.floating_ip_create(admin_context,
                                   {'address': str(address),
                                    'pool': pool,