Add -L to follow redirects

As per the comments in git-tips#154, use -L to follow the redirect for curl. The tip as written does not currently work as it downloads the html for the redirect page instead.

tips.json

@@ -104,7 +104,7 @@
 		"tip": "git add -p"
 	}, {
 		"title": "Get git bash completion",
-		"tip": "curl http://git.io/vfhol > ~/.git-completion.bash && echo '[ -f ~/.git-completion.bash ] && . ~/.git-completion.bash' >> ~/.bashrc"
+		"tip": "curl -L http://git.io/vfhol > ~/.git-completion.bash && echo '[ -f ~/.git-completion.bash ] && . ~/.git-completion.bash' >> ~/.bashrc"
 	}, {
 		"title": "What changed since two weeks?",
 		"tip": "git log --no-merges --raw --since='2 weeks ago'",