Fix a memory leak in `git_pathspec__vinit`.
Fix a memory leak in `git_config_iterator_glob_new`.
Fix a memory leak in `config_parse`.
Fix a memory leak in `hash_and_save` and `inject_object`.
Fix a double free issue in `git_blame__alloc`.

`git_blame_free` already calls `git__free` on `gbr`.
Incorporate @ethomson's suggestions.
Incorporate @arrbee's suggestions.
Merge pull request #2043 from arthurschreiber/arthur/fix-memory-leaks

Fix a bunch of memory leaks.