Log pidfile creation and removal

The pidfile is also used as a lock file. Add logs to reveal incorrect
creation or removal of the pidfile.

When creating a pidfile we will see:

    INFO | Created pidfile "/tmp/socket_vmnet.pid" for process 37297

When removing we will see:

    INFO | Removed pidfile "/tmp/socket_vmnet.pid" for process 37297

Signed-off-by: Nir Soffer <nirsof@gmail.com>

Author: nirs

main.c

@@ -358,7 +358,9 @@ static void remove_pidfile(const char *pidfile)
 {
   if (unlink(pidfile) != 0) {
     ERRORF("Failed to remove pidfile: \"%s\": %s", pidfile, strerror(errno));
+    return;
   }
+  INFOF("Removed pidfile \"%s\" for process %d", pidfile, getpid());
 }
 
 static int create_pidfile(const char *pidfile)
@@ -385,6 +387,7 @@ static int create_pidfile(const char *pidfile)
     return -1;
   }
 
+  INFOF("Created pidfile \"%s\" for process %d", pidfile, getpid());
   return fd;
 }