log2zulip: use a Zulip virtualenv if available.

This makes it easier to use log2zulip in a Zulip server environment.

bots/log2zulip

@@ -1,16 +1,25 @@
 #!/usr/bin/env python
 from __future__ import print_function
-import subprocess
-import os
-import sys
-import shutil
+
 import errno
-import json
-import ujson
+import os
 import platform
 import re
+import sys
+import shutil
+import subprocess
 import traceback
 
+try:
+    # Use the Zulip virtualenv if available
+    sys.path.append(os.path.join(os.path.dirname(__file__), ".."))
+    import scripts.lib.setup_path_on_import
+except ImportError:
+    pass
+
+import json
+import ujson
+
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "../api"))
 import zulip