~/.zshrc: Report hg branch as "default" if no .hg/branch

.zshrc

function repo_branch {
	if $HOME/.bin/up .hg > /dev/null 2> /dev/null; then
		echo "%{$fg[green]%}$(cat `$HOME/.bin/up .hg`/.hg/branch)%{$reset_color%}"
		echo "%{$fg[green]%}$(cat `$HOME/.bin/up .hg`/.hg/branch 2> /dev/null || echo default)%{$reset_color%}"
	elif git branch > /dev/null 2> /dev/null; then
		echo "%{$fg[green]%}$(git branch --no-color | sed -En 's/^\* (.*)/\1/p')%{$reset_color%}"
	fi