doc: update curl usage in COLLABORATOR_GUIDE

Github now redirects the patch urls hosted on github.com, making it
necessary to enable curl redirect handling to obtain patches in the
merge process.

Example (before and after):
https://github.com/iojs/io.js/pull/1382.patch
https://patch-diff.githubusercontent.com/raw/iojs/io.js/pull/1382.patch

PR-URL: https://github.com/iojs/io.js/pull/1382
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

diff --git a/COLLABORATOR_GUIDE.md b/COLLABORATOR_GUIDE.md
index 6502532..c4b06cb 100644 (file)
--- a/COLLABORATOR_GUIDE.md
+++ b/COLLABORATOR_GUIDE.md
@@ -132,7 +132,7 @@ $ git merge --ff-only origin/v1.x
 Apply external patches
 
 ```text
-$ curl https://github.com/iojs/io.js/pull/xxx.patch | git am --whitespace=fix
+$ curl -L https://github.com/iojs/io.js/pull/xxx.patch | git am --whitespace=fix
 ```
 
 Check and re-review the changes