checkout: set ignorecase=0 when config lookup fails
checkout: set ignorecase=0 when config lookup fails

When `git_repository__cvar` fails we may end up with a
`ignorecase` value of `-1`. As we subsequently check if
`ignorecase` is non-zero, we may end up reporting that data
should be removed when in fact it should not.

Err on the safer side and set `ignorecase = 0` when
`git_repository__cvar` fails.

Corillian/libgit2,Corillian/libgit2,stewid/libgit2,Corillian/libgit2,stewid/libgit2,stewid/libgit2,Corillian/libgit2,Corillian/libgit2,stewid/libgit2,stewid/libgit2,Corillian/libgit2,stewid/libgit2