Corrects typo in instance models and service

The get_default_configuration_template() function in Instance was
misspelled as 'configration'. The function is also called from the
InstanceController class.

Closes-Bug: #1331135
Change-Id: I95416b0c5d49a46d19edd548c36ec619f580a8e0
Merge "Corrects typo in instance models and service"