add git-prompt candidate

shrc

@@ -1049,6 +1049,7 @@ __my_ps1_moc(){
 }
 
 for f in /usr/share/git/git-prompt.sh \
+    /etc/bash_completion.d/git-prompt \
     /opt/local/share/git-core/git-prompt.sh \
     /opt/local/share/doc/git-core/contrib/completion/git-prompt.sh
 do