Remove functions wrapping Zeus

Project should be moving over to spring, as this is the 'blessed'
approach and is part of suspenders. Leaving these functions around adds
yet another layer of indirection to consider when trying to run these
commands:

* function wrapper
* binstub
* rbenv shim
* actual binary

zsh/functions/rake

@@ -1,7 +0,0 @@
-rake() {
-  if [ -S .zeus.sock ]; then
-    zeus rake "$@"
-  else
-    command rake "$@"
-  fi
-}

zsh/functions/rspec

@@ -1,7 +0,0 @@
-rspec() {
-  if [ -S .zeus.sock ]; then
-    zeus rspec "$@"
-  else
-    command rspec "$@"
-  fi
-}