Properly update the shm_open/shm_unlink symbol versioning metadata after

these functions were moved into the kernel:
- Move the version entries from gen/ to sys/.  Since the ABI of the actual
  routines did not change, I'm still exporting them as FBSD 1.0 on purpose.
- Add FBSD-private versions for the _ and __sys_ variants.

lib/libc/gen/Symbol.map

@@ -223,8 +223,6 @@ FBSD_1.0 {
 	posix_madvise;
 	popen;
 	pclose;
-	shm_open;
-	shm_unlink;
 	pselect;
 	psignal;
 	raise;

lib/libc/sys/Symbol.map

@@ -265,6 +265,8 @@ FBSD_1.0 {
 	setsockopt;
 	settimeofday;
 	setuid;
+	shm_open;
+	shm_unlink;
 	shmat;
 	shmctl;
 	shmdt;
@@ -876,6 +878,10 @@ FBSDprivate_1.0 {
 	__sys_settimeofday;
 	_setuid;
 	__sys_setuid;
+	_shm_open;
+	__sys_shm_open;
+	_shm_unlink;
+	__sys_shm_unlink;
 	_shmat;
 	__sys_shmat;
 	_shmctl;