Checks if requirements overlap between head and branch reqs

If there is a requirement in head and branches, and are not equal,
check if the head requirement is overlapping with branch one,
if not it triggers an error

Change-Id: I159e4608a5d345e57ae24fd19b1c54c1de4ed9d9
Closes-Bug: #1274731
Merge "Checks if requirements overlap between head and branch reqs"