Split diff line by '\t' for metadata and path

This protects against `.split(None)` which uses consecutive whitespace
as a separator to overlook paths where a single space is the filename.
For example, in this diff line:

line = ':100644 000000 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
0000000000000000000000000000000000000000 D       '

The deleted file is a file named ' ' (just one space).  It's entirely
possible to commit this, remove, and to produce the following output
from `git diff`:

git diff --name-status <SHA1> <SHA2>
D
M       path/to/another/file.py
...

This would cause the initial `.split(None, 5)` to fail as it will count
all consecutive whitespace as a separator, disregarding the ' ' (single
space)  filename.

0 files changed, 0 insertions, 0 deletions