[PATCH] setup: fix runcmd() usage on darwin

[Adam Simpkins]

# HG changeset patch
# User Adam Simpkins <simpkins at fb.com>
# Date 1498672237 25200
#      Wed Jun 28 10:50:37 2017 -0700
# Node ID 649cb52c8cd94ab98068004e40bf9947de62a0ce
# Parent  6ef5f0c95d643d114262f8c6689a6fc02adb0da7
setup: fix runcmd() usage on darwin

Fix one invocation of runcmd() that was missed in the recent change to
make runcmd() also return the process exit status.

diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -814,7 +814,7 @@
     setupversion = version.split('+', 1)[0]
 
 if sys.platform == 'darwin' and os.path.exists('/usr/bin/xcodebuild'):
-    version = runcmd(['/usr/bin/xcodebuild', '-version'], {})[0].splitlines()
+    version = runcmd(['/usr/bin/xcodebuild', '-version'], {})[1].splitlines()
     if version:
         version = version[0]
         if sys.version_info[0] == 3: