Import sys in repo.py.

The find function in repo.py calls sys.exit on error. Without this import that
call to exit will fail, masking the actual error message. This patch fixes that.

llvm-svn: 302584

lldb/scripts/Xcode/repo.py

@@ -3,6 +3,7 @@ import os
 import re
 import shutil
 import subprocess
+import sys
 
 def identifier():
 	try: