possible solution to nullPointerException in InstructorCourseEditPage
modify asp file to not show the join link element in source code if the key does not exist
Revert "modify asp file to not show the join link element in source code if the key does not exist"

This reverts commit b42875f5640d500d079d40570ebb6c2f6bc1709c.
[2242] instructorCourseEdit: Null pointer exception

fixes #2242
modify jsp to not show join link element when key does not exist
Merge branch 'master' into Issue2242
[2242] instructorCourseEdit: Null pointer exception

fixes #2242
Merge branch 'master' into AccessControl