runc spec, libct/int: do not add ambient capabilities

Commit 98fe566 removed inheritable capabilities from the example spec
(used by runc spec) and from the libcontainer/integration test config,
but neglected to also remove ambient capabilities.

An ambient capability could only be set if the same inheritable
capability is set, so as a result of the above change ambient
capabilities were not set (but due to a bug in gocapability package,
those errors are never reported).

Once we start using a library with the fix [1], that bug will become
apparent (both bats-based and libct/int tests will fail).

[1]: kolyshkin/capability#3

Fixes: 98fe566 ("runc: do not set inheritable capabilities")
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/integration/template_test.go

@@ -75,22 +75,6 @@ func newTemplateConfig(t *testing.T, p *tParam) *configs.Config {
 				"CAP_KILL",
 				"CAP_AUDIT_WRITE",
 			},
-			Ambient: []string{
-				"CAP_CHOWN",
-				"CAP_DAC_OVERRIDE",
-				"CAP_FSETID",
-				"CAP_FOWNER",
-				"CAP_MKNOD",
-				"CAP_NET_RAW",
-				"CAP_SETGID",
-				"CAP_SETUID",
-				"CAP_SETFCAP",
-				"CAP_SETPCAP",
-				"CAP_NET_BIND_SERVICE",
-				"CAP_SYS_CHROOT",
-				"CAP_KILL",
-				"CAP_AUDIT_WRITE",
-			},
 			Effective: []string{
 				"CAP_CHOWN",
 				"CAP_DAC_OVERRIDE",

libcontainer/specconv/example.go

@@ -41,11 +41,6 @@ func Example() *specs.Spec {
 					"CAP_KILL",
 					"CAP_NET_BIND_SERVICE",
 				},
-				Ambient: []string{
-					"CAP_AUDIT_WRITE",
-					"CAP_KILL",
-					"CAP_NET_BIND_SERVICE",
-				},
 				Effective: []string{
 					"CAP_AUDIT_WRITE",
 					"CAP_KILL",