brew update failure with git formula

brew_config.shell

$ brew config
HOMEBREW_VERSION: 1.0.9-41-g0028cf9
ORIGIN: https://github.com/Homebrew/brew
HEAD: 0028cf9fb85e7fecb4ad803a817600068c821dc9
Last commit: 14 hours ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: 3ade4a12394af41ad4815edd7b1acdbd0b95b56f
Core tap last commit: 57 minutes ago
HOMEBREW_PREFIX: /usr/local
HOMEBREW_REPOSITORY: /usr/local/Homebrew
HOMEBREW_CELLAR: /usr/local/Cellar
HOMEBREW_BOTTLE_DOMAIN: https://homebrew.bintray.com
CPU: quad-core 64-bit haswell
Homebrew Ruby: 2.0.0-p648
GCC-4.2: build 5666
Clang: 8.0 build 800
Git: 2.9.3 => /Applications/Xcode.app/Contents/Developer/usr/bin/git
Perl: /usr/bin/perl
Python: /usr/local/bin/python => /usr/local/Cellar/python/2.7.12_2/Frameworks/Python.framework/Versions/2.7/bin/python2.7
Ruby: /usr/bin/ruby => /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby
Java: N/A
macOS: 10.11.6-x86_64
Xcode: 8.1
CLT: 7.3.1.0.1.1461711523
X11: 2.7.9 => /opt/X11

error_again

$ brew update --force
Already up-to-date.

$ brew update --force
Already up-to-date.

$ brew install git
==> Downloading https://homebrew.bintray.com/bottles/git-2.10.2.el_capitan.bottle.1.tar.gz
Already downloaded: /Users/ddbeck/Library/Caches/Homebrew/git-2.10.2.el_capitan.bottle.1.tar.gz
==> Pouring git-2.10.2.el_capitan.bottle.1.tar.gz
==> Caveats
Bash completion has been installed to:
  /usr/local/etc/bash_completion.d

zsh completion has been installed to:
  /usr/local/share/zsh/site-functions

Emacs Lisp files have been installed to:
  /usr/local/share/emacs/site-lisp/git
==> Summary
🍺  /usr/local/Cellar/git/2.10.2: 1,445 files, 31.8M

$ brew update --force
fatal: unable to access 'https://github.com/Homebrew/brew/': SSL: can't load CA certificate file /usr/local/share/ca-bundle.crt
fatal: unable to access 'https://github.com/caskroom/homebrew-cask/': SSL: can't load CA certificate file /usr/local/share/ca-bundle.crt
fatal: unable to access 'https://github.com/Homebrew/homebrew-dupes/': SSL: can't load CA certificate file /usr/local/share/ca-bundle.crt
fatal: unable to access 'https://github.com/Homebrew/homebrew-core/': SSL: can't load CA certificate file /usr/local/share/ca-bundle.crt
Error: Fetching /usr/local/Homebrew failed!
Fetching /usr/local/Homebrew/Library/Taps/caskroom/homebrew-cask failed!
Fetching /usr/local/Homebrew/Library/Taps/homebrew/homebrew-dupes failed!
Fetching /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core failed!

$ brew uninstall git
Uninstalling /usr/local/Cellar/git/2.10.2... (1,445 files, 31.8M)

$ brew update --force
Already up-to-date.