[FD-9] Pushing tags triggers commit hook, which fails flod

[pbeckingham]

$ git tag -a s1.3.0 -m "Start of v1.3.0 development"; git push --tags
Counting objects: 1, done.
Writing objects: 100% (1/1), 174 bytes | 0 bytes/s, done.
Total 1 (delta 0), reused 0 (delta 0)
remote: fatal: Invalid revision range 0000000000000000000000000000000000000000..1c8e820a89da21bb8c999aabb5e449153f9d770b
To git.tasktools.org:EX/tasksh.git

• [new tag] s1.3.0 -> s1.3.0