move function to create the TLS key log file to a separate file

interop/utils/logging.go

@@ -0,0 +1,19 @@
+package utils
+
+import (
+	"io"
+	"os"
+)
+
+// GetSSLKeyLog creates a file for the TLS key log
+func GetSSLKeyLog() (io.WriteCloser, error) {
+	filename := os.Getenv("SSLKEYLOGFILE")
+	if len(filename) == 0 {
+		return nil, nil
+	}
+	f, err := os.Create(filename)
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}