Fix Concept Display Due to Wrong Concept ID Value Being Passed

This happens when the module attempts to populate the concept field tag with an existing value (i.e. the initial value). Instead of populating DWR fails with the error as displayed in the following snapshot.

Reason: This happens because the the JSTL ${model.obj} in line https://github.com/openmrs/openmrs-module-legacyui/blob/master/omod/src/main/webapp/fieldGen/concept.jsp#L5 effectively calls `Concept.toString()` which returns a string of the form "Concept #<concept_id>" which then can not converted to integer when DWR makes the remote call.

Solution: Change the code to ensure the initialValue field is populated with a concept_id string.