Remove extra mkdir command

Makefile

@@ -9,8 +9,7 @@ install: dotfiles
 	install -m 0644 dot.tcshrc $(prefix)/.tcshrc
 	install -m 0644 dot.vimrc $(prefix)/.vimrc
 	install -m 0644 dot.zshenv $(prefix)/.zshenv
-	mkdir -p $(prefix)/.config/fish
-	install -m 0644 dot.config/fish/config.fish $(prefix)/.config/fish/config.fish
+	install -p -m 0644 dot.config/fish/config.fish $(prefix)/.config/fish/config.fish
 
 diff:
 	diff dot.bash_profile $(prefix)/.bash_profile || true 2>/dev/null