Return if DumpKernelStack can't find the kernel stack file.
Return if DumpKernelStack can't find the kernel stack file.

Change-Id: I1d974632d98028f0b4d77a47fc22f3aac53f850c

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst