fix: appease linter on darwin (#11154)

Fixing up some linting errors that show up on Darwin, but not in CI.

agent/agentproc/proc_other.go

@@ -7,18 +7,18 @@ import (
 	"github.com/spf13/afero"
 )
 
-func (p *Process) Niceness(sc Syscaller) (int, error) {
+func (*Process) Niceness(Syscaller) (int, error) {
 	return 0, errUnimplemented
 }
 
-func (p *Process) SetNiceness(sc Syscaller, score int) error {
+func (*Process) SetNiceness(Syscaller, int) error {
 	return errUnimplemented
 }
 
-func (p *Process) Cmd() string {
+func (*Process) Cmd() string {
 	return ""
 }
 
-func List(fs afero.Fs, syscaller Syscaller) ([]*Process, error) {
+func List(afero.Fs, Syscaller) ([]*Process, error) {
 	return nil, errUnimplemented
 }

agent/agentproc/syscaller.go

@@ -10,6 +10,7 @@ type Syscaller interface {
 	Kill(pid int32, sig syscall.Signal) error
 }
 
+// nolint: unused // used on some but no all platforms
 const defaultProcDir = "/proc"
 
 type Process struct {

agent/agentproc/syscaller_other.go

@@ -17,14 +17,14 @@ var errUnimplemented = xerrors.New("unimplemented")
 
 type nopSyscaller struct{}
 
-func (nopSyscaller) SetPriority(pid int32, priority int) error {
+func (nopSyscaller) SetPriority(int32, int) error {
 	return errUnimplemented
 }
 
-func (nopSyscaller) GetPriority(pid int32) (int, error) {
+func (nopSyscaller) GetPriority(int32) (int, error) {
 	return 0, errUnimplemented
 }
 
-func (nopSyscaller) Kill(pid int32, sig syscall.Signal) error {
+func (nopSyscaller) Kill(int32, syscall.Signal) error {
 	return errUnimplemented
 }