Fix 'latest' symlink.

[grahamgower]

---

t490:g $ mkdir main
t490:g $ ln -sf main latest
t490:g $ ls -lR
.:
total 0
lrwxrwxrwx 1 grg grg  4 Dec  7 20:11 latest -> main/
drwxr-xr-x 2 grg grg 40 Dec  7 20:11 main/

./main:
total 0

t490:g $ ln -sf main latest
t490:g $ ls -lR
.:
total 0
lrwxrwxrwx 1 grg grg  4 Dec  7 20:11 latest -> main/
drwxr-xr-x 2 grg grg 60 Dec  7 20:11 main/

./main:
total 0
lrwxrwxrwx 1 grg grg 4 Dec  7 20:11 main -> main

t490:g $ rm -fr *
t490:g $ mkdir main
t490:g $ ln -sfT main latest
t490:g $ ln -sfT main latest
t490:g $ ln -sfT main latest
t490:g $ ls -lR
.:
total 0
lrwxrwxrwx 1 grg grg  4 Dec  7 20:12 latest -> main/
drwxr-xr-x 2 grg grg 40 Dec  7 20:12 main/

./main:
total 0