Swap ESC and CAPSLOCK keys on CentOS [MEMO]

CentOS's keyboard configuration tools does not have an option to switch ESC and
CAPSLOCK keys. So you need to do the steps.

Create a file ~/.speedswapper with the following content:

! Swap caps lock and escape
remove Lock = Caps_Lock
keysym Escape = Caps_Lock
keysym Caps_Lock = Escape
add Lock = Caps_Lock

The following command will do the switch
$ xmodmap .speedswapper

Refer to http://vim.wikia.com/wiki/Map_caps_lock_to_escape_in_XWindows