Set process return code of 1 in set-xcode-analyzer when Xcode needs to be quit.  Fixes <rdar://problem/12983031>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172256 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/scan-build/set-xcode-analyzer b/tools/scan-build/set-xcode-analyzer
index a32e676..3076b39 100755
--- a/tools/scan-build/set-xcode-analyzer
+++ b/tools/scan-build/set-xcode-analyzer
@@ -76,7 +76,7 @@
   for x in NSWorkspace.sharedWorkspace().runningApplications():
     if x.localizedName().find("Xcode") >= 0:
       print "(-) You must quit Xcode first before modifying its configuration files."
-      return
+      sys.exit(1)
 
   isBuiltinAnalyzer = False
   if options.path: