fix mysql attribute error (https://github.com/opscode-cookbooks/mysql/pull/93)

NoMethodError
-------------
Undefined method or attribute `ipaddress' on `node'


Cookbook Trace:
---------------
  /etc/chef/chef-cookbooks/mysql/attributes/server.rb:20:in `from_file'


Relevant File Content:
----------------------
/etc/chef/chef-cookbooks/mysql/attributes/server.rb:

 13:  # Unless required by applicable law or agreed to in writing, software
 14:  # distributed under the License is distributed on an "AS IS" BASIS,
 15:  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 16:  # See the License for the specific language governing permissions and
 17:  # limitations under the License.
 18:  #
 19:  
 20>> default['mysql']['bind_address']               = attribute?('cloud') ? cloud['local_ipv4'] : ipaddress