UpdateUserTask to ignore unmapped properties

A post processor has been added to update User Info in OpenMRS from OpenID Data.
The issues:

1. if some properties are not present, it creates too many warnings (gender, middle name,...)
2. if roles is not found in the OpenID user info, the roles of the user are cleared

The expected behaviour:
if some mappings are not defined in the file oauth2.properties, no operation should be done concerning the corresponding properties.
For instance:

• if the property openmrs.mapping.user.roles is not defined, the roles should not be updated and no warning in the logs
• if the property openmrs.mapping.user.gender is not defined, the gender is not updated and no warning in the logs.