Add handler for SIGUSR1 based on feedback regarding when to dump
goroutine stacks. This will also dump goroutine stack traces on SIGQUIT
followed by a hard-exit from the daemon.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Upstream-commit: 95fcf76cc64a4acf95c168e8d8607e3acf405c13
Component: engine