Add `git_remote_dup`.
Merge pull request #2045 from arthurschreiber/arthur/add-git_remote_dup

Add `git_remote_dup`.
Don't duplicate state that's only used when fetching.
We don't need memset here.
Align git_signature_dup.

This changes git_signature_dup to actually honor oom conditions raised by
the call to git__strdup. It also aligns it with the error code return
pattern used everywhere else.
Align git_tree_entry_dup.
Merge pull request #2048 from arthurschreiber/arthur/add-git_remote_dup

Implement @cmn's suggestions for `git_remote_dup`.
Merge pull request #2047 from arthurschreiber/arthur/fix-dup-functions

Align `*_dup` functions
unnecessary include
Move libgit2 settings out of util
Merge pull request #2049 from ethomson/common

Common
refs: remove the _with_log differentiation

Any well-behaved program should write a descriptive message to the
reflog whenever it updates a reference. Let's make this more prominent
by removing the version without the reflog parameters.
Merge pull request #2050 from libgit2/cmn/always-reflog-message

refs: remove the _with_log differentiation