Set xcode path earlier in clang update.py

macOS's system svn binary needs DEVELOPER_DIR to be set when Xcode
isn't in a standard location and xcode-select wasn't run.

We used to set DEVELOPER_DIR after running svn (it's also needed
for the build steps); this moves it to before svn runs.

Bug: 861487
Change-Id: Ice74574804fe4a84e8029c869fdfcada45e0f6b5
Reviewed-on: https://chromium-review.googlesource.com/c/1474256
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632607}
1 file changed