Previously,
* typing `gf` in domain names (for example google.com) in normal buffers
* typing `<tab>` in domain names in the minibuffer
would start pinging that domain name. This is not really useful, so
disable it.
Fixes#2654.
Helm-flx, which is included as a core package, requires a minimum Emacs
version of 24.4. As it stands attempting to install Spacemacs on Emacs
24.3 or below will break on helm-flx.
