Redirect update url to correct controller

CompoundMetricConfigurationController was using update method from
MetricConfigurationController

signed-off-by: Pedro Paulo Vezza Campos <pedro@vezza.com.br>
Missing method update on the compound metric class

signed-off-by: Thiago Kenji Okada <thiago.mast3r@gmail.com>
Added unit tests for the update method

signed-off-by: Pedro Paulo Vezza Campos <pedro@vezza.com.br>
Added acceptance test to Compound Metric edit configuration

signed-off-by: Pedro Paulo Vezza Campos <pedro@vezza.com.br>
Fixes message of successful compound metric update

signed-off-by: Thiago Kenji Okada <thiago.mast3r@gmail.com>
Added missing mock to compound metric configuration

signed-off-by: Pedro Vezza <pedro@vezza.com.br>
Merge pull request #78 from mezuro/broken_compound_update

Broken compound update