When zkg is bundled with Zeek, prepend Zeek's Python module path

Prepending instead of appending ensures that the bundled zkg picks the
zeekpkg module shipped with Zeek, not any others available elsewhere
in Python's search path.

zkg

@@ -33,11 +33,13 @@ except ImportError as error:
           file=sys.stderr)
     sys.exit(1)
 
-# For Zeek-bundled installation, explictly add the Python path we've
-# installed ourselves under, so we find the zeekpkg module:
+# For Zeek-bundled installation, prepend the Python path of the Zeek
+# installation. This ensures we find the matching zeekpkg module
+# first, avoiding potential conflicts with installations elsewhere on
+# the system.
 ZEEK_PYTHON_DIR = '@PY_MOD_INSTALL_DIR@'
 if os.path.isdir(ZEEK_PYTHON_DIR):
-    sys.path.append(os.path.abspath(ZEEK_PYTHON_DIR))
+    sys.path.insert(0, os.path.abspath(ZEEK_PYTHON_DIR))
 else:
     ZEEK_PYTHON_DIR = None