pkg/signal: remove stubs for deprecated package

The pkg/signal package was moved to github.com/moby/sys/signal in
28409ca6c76030ef1cd277cf73223a47cf3f1dbe. The DefaultStopSignal const was
deprecated in e53f65a9168aaf4289a490bd56d9e05b46c08bec, and the DumpStacks
function was moved to pkg/stack in ea5c94cdb94f74808958732d8b3254921f52be4f,
all of which are included in the 22.x release, so we can safely remove these
from master.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

pkg/signal/signal_deprecated.go

@@ -1,55 +0,0 @@
-// Package signal provides helper functions for dealing with signals across
-// various operating systems.
-package signal // import "github.com/docker/docker/pkg/signal"
-
-import (
-	"github.com/docker/docker/pkg/stack"
-	msignal "github.com/moby/sys/signal"
-)
-
-var (
-	// DumpStacks appends the runtime stack into file in dir and returns full path
-	// to that file.
-	// Deprecated: use github.com/docker/docker/pkg/stack.Dump instead.
-	DumpStacks = stack.DumpToFile
-
-	// CatchAll catches all signals and relays them to the specified channel.
-	// SIGURG is not handled, as it's used by the Go runtime to support
-	// preemptable system calls.
-	// Deprecated: use github.com/moby/sys/signal.CatchAll instead
-	CatchAll = msignal.CatchAll
-
-	// StopCatch stops catching the signals and closes the specified channel.
-	// Deprecated: use github.com/moby/sys/signal.StopCatch instead
-	StopCatch = msignal.StopCatch
-
-	// ParseSignal translates a string to a valid syscall signal.
-	// It returns an error if the signal map doesn't include the given signal.
-	// Deprecated: use github.com/moby/sys/signal.ParseSignal instead
-	ParseSignal = msignal.ParseSignal
-
-	// ValidSignalForPlatform returns true if a signal is valid on the platform
-	// Deprecated: use github.com/moby/sys/signal.ValidSignalForPlatform instead
-	ValidSignalForPlatform = msignal.ValidSignalForPlatform
-
-	// SignalMap is a map of signals for the current platform.
-	// Deprecated: use github.com/moby/sys/signal.SignalMap instead
-	SignalMap = msignal.SignalMap
-)
-
-// Signals used in cli/command
-const (
-	// SIGCHLD is a signal sent to a process when a child process terminates, is interrupted, or resumes after being interrupted.
-	// Deprecated: use github.com/moby/sys/signal.SIGCHLD instead
-	SIGCHLD = msignal.SIGCHLD
-	// SIGWINCH is a signal sent to a process when its controlling terminal changes its size
-	// Deprecated: use github.com/moby/sys/signal.SIGWINCH instead
-	SIGWINCH = msignal.SIGWINCH
-	// SIGPIPE is a signal sent to a process when a pipe is written to before the other end is open for reading
-	// Deprecated: use github.com/moby/sys/signal.SIGPIPE instead
-	SIGPIPE = msignal.SIGPIPE
-
-	// DefaultStopSignal has been deprecated and removed. The default value is
-	// now defined in github.com/docker/docker/container. Clients should omit
-	// the container's stop-signal field if the default should be used.
-)