git plugin: make gclean safer, introduce gpristine

plugins/git/git.plugin.zsh

@@ -71,7 +71,8 @@ alias gcan!='git commit -v -a -s --no-edit --amend'
 alias gcb='git checkout -b'
 alias gcf='git config --list'
 alias gcl='git clone --recursive'
-alias gclean='git reset --hard && git clean -dfx'
+alias gclean='git clean -fd'
+alias gpristine='git reset --hard && git clean -dfx'
 alias gcm='git checkout master'
 alias gcmsg='git commit -m'
 alias gco='git checkout'