feat(firecracker): launch with control socket instead of config file

Firecracker currently boots via --no-api --config-file, which disables
its control socket entirely. Switch to --api-sock so the socket stays
open and reachable after the guest starts, instead of driving
everything through a static config file.

Signed-off-by: Anamika AggarwaL <anamikaagg18@gmail.com>

Author: Anamika1608

pkg/unikontainers/hypervisors/firecracker.go

@@ -108,9 +108,9 @@ func (fc *Firecracker) BuildExecCmd(args types.ExecArgs, ukernel types.Unikernel
 	// options in FC, since the string return value of the Monitor related
 	// functions in the unikernel interface do not integrate well with FC's
 	// json configuration.
-	cmdString := fc.Path() + " --no-api --config-file "
+	apiSockPath := filepath.Join("/tmp/", args.ContainerID+".sock")
+	cmdString := fc.Path() + " --api-sock " + apiSockPath
 	JSONConfigFile := filepath.Join("/tmp/", FCJsonFilename)
-	cmdString += JSONConfigFile
 	if !args.Seccomp {
 		cmdString += " --no-seccomp"
 	}