Fix for filenames with spaces

[kwstannard]

How to replicate the problem:

git co -b foo
echo hello > "a b"
git add "a b"
git commit -m x
git co master
git co -b bar
echo world > "a b"
git add "a b"
git commit -m y
git rebase foo
git conflicted

Prior to this, conflicted would try to load for a file "a" because awk thinks the space in the name is a column separator.

[christoomey]

Thanks for this fix @kwstannard! Also, thanks for the quality summary with repro steps and everything. Code's much clearer as well. Wins all around 👍

[kwstannard]

Glad I could help. Thank you for this project.