bitbake: taskdata: Don't add dependencies on tasks that don't exist

"bitbake meta-toolchain" with qemu image testing enabled causes problems
since it adds a task after do_rootfs which doesn't exist in this case.

We should simply ignore these extra dependencies rather than adding
them in which is what this patch does (adding a debug message when this
happens).

(Bitbake rev: 843d3d6b0a7eb2e2f7b50c555767f5385df16ede)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/taskdata.py

@@ -176,6 +176,9 @@ class TaskData:
             # Work out task dependencies
             parentids = []
             for dep in task_deps['parents'][task]:
+                if dep not in task_deps['tasks']:
+                    bb.debug(2, "Not adding dependeny of %s on %s since %s does not exist" % (task, dep, dep))
+                    continue
                 parentid = self.gettask_id(fn, dep)
                 parentids.append(parentid)
             taskid = self.gettask_id(fn, task)