hub: fix various uninitialized variables

Change-Id: I49ac89a59f12fc8f69d822e09dafd9c0c7509d16
Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
kernel/return_address.c: hide warning

Change-Id: I8e3d1af07d00ed10a7a340b612b504c46a743d06
Signed-off-by: Dennis Rassmann <showp1984@gmail.com>