return allocation id for vpc address.

lib/ansible/modules/cloud/amazon/ec2_eip.py

@@ -286,7 +286,7 @@ def ensure_present(ec2, domain, address, device_id,
 
         changed = changed or assoc_result['changed']
 
-    return {'changed': changed, 'public_ip': address.public_ip}
+    return {'changed': changed, 'public_ip': address.public_ip, 'allocation_id': address.allocation_id}
 
 
 def ensure_absent(ec2, domain, address, device_id, check_mode, isinstance=True):
@@ -362,7 +362,7 @@ def main():
                                     module.check_mode, isinstance=is_instance)
             else:
                 address = allocate_address(ec2, domain, reuse_existing_ip_allowed)
-                result = {'changed': True, 'public_ip': address.public_ip}
+                result = {'changed': True, 'public_ip': address.public_ip, 'allocation_id': address.allocation_id}
         else:
             if device_id:
                 disassociated = ensure_absent(ec2, domain, address, device_id, module.check_mode, isinstance=is_instance)