main: corrected do_switch_root()

do_switch_root now mount moves "/dev", "/proc", "/sys", "/run" and
removes the old root recursively.

src/shared/util.c

@@ -3139,7 +3139,7 @@ int get_ctty(pid_t pid, dev_t *_devnr, char **r) {
         return 0;
 }
 
-static int rm_rf_children(int fd, bool only_dirs, bool honour_sticky) {
+int rm_rf_children(int fd, bool only_dirs, bool honour_sticky) {
         DIR *d;
         int ret = 0;
 

src/shared/util.h

@@ -349,6 +349,7 @@ int get_ctty(pid_t, dev_t *_devnr, char **r);
 int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid);
 int fchmod_and_fchown(int fd, mode_t mode, uid_t uid, gid_t gid);
 
+int rm_rf_children(int fd, bool only_dirs, bool honour_sticky);
 int rm_rf(const char *path, bool only_dirs, bool delete_root, bool honour_sticky);
 
 int pipe_eof(int fd);