vty: fix unreachable code (error msg on trunk alloc fail)

When a trunk is selected that does not exist, a new one is created. In
this case the VTY would print an error message but the function exits
early. The code that would print the error is unreachable.

Change-Id: Ie8c3b083174eb8209df2c06f65db6d7bbfaa87f7
fixes: CID#210637
1 file changed