Improve nsexec logging

* Simplify logging function
* Logs contain __FUNCTION__:__LINE__
* Bail uses write_log

Co-authored-by: Julia Nedialkova <julianedialkova@hotmail.com>
Co-authored-by: Danail Branekov <danailster@gmail.com>
Signed-off-by: Georgi Sabev <georgethebeatle@gmail.com>

exec.go

@@ -136,6 +136,12 @@ func execProcess(context *cli.Context) (int, error) {
 	if err != nil {
 		return -1, err
 	}
+
+	logLevel := "info"
+	if context.GlobalBool("debug") {
+		logLevel = "debug"
+	}
+
 	r := &runner{
 		enableSubreaper: false,
 		shouldDestroy:   false,
@@ -146,6 +152,7 @@ func execProcess(context *cli.Context) (int, error) {
 		action:          CT_ACT_RUN,
 		init:            false,
 		preserveFDs:     context.Int("preserve-fds"),
+		logLevel:        logLevel,
 	}
 	return r.run(p)
 }