Fix install-sysroot.py script not working behind proxy.

build/linux/sysroot_scripts/install-sysroot.py

Index: build/linux/sysroot_scripts/install-sysroot.py
diff --git a/build/linux/sysroot_scripts/install-sysroot.py b/build/linux/sysroot_scripts/install-sysroot.py
index 109d5532b518bcbdfa96d44de4b395bcf6ba1898..13b089120680ff3274b8f18763baebf964b6b23d 100755
--- a/build/linux/sysroot_scripts/install-sysroot.py
+++ b/build/linux/sysroot_scripts/install-sysroot.py
@@ -25,7 +25,7 @@ import re
 import shutil
 import subprocess
 import sys
-import urllib
+import urllib2
 
 SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
 sys.path.append(os.path.dirname(os.path.dirname(SCRIPT_DIR)))
@@ -248,7 +248,9 @@ def InstallSysroot(target_platform, target_arch):
   sys.stderr.flush()
   for _ in range(3):
     try:
-      urllib.urlretrieve(url, tarball)
+      response = urllib2.urlopen(url)
+      with open(tarball, "wb") as f:
+        f.write(response.read())
       break
     except:
       pass