X: remove eval $(gpg-agent --daemon)

gpg is smarter now, the command 'gpg' will run and get information from
gpg-agent automatically. So this line is unnecessary now.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
zsh: update zshrc, mainly for prompt

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>