run, create: add new security-opt proc-opts

it allows to customize the options passed down to the OCI runtime for
setting up the /proc mount.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

pkg/spec/security.go

@@ -76,6 +76,8 @@ func (c *SecurityConfig) SetSecurityOpts(runtime *libpod.Runtime, securityOpts [
 			}
 
 			switch con[0] {
+			case "proc-opts":
+				c.ProcOpts = strings.Split(con[1], ",")
 			case "label":
 				c.LabelOpts = append(c.LabelOpts, con[1])
 			case "apparmor":