Issue #2377: Make importlib the implementation of __import__().

importlib._bootstrap is now frozen into Python/importlib.h and stored
as _frozen_importlib in sys.modules. Py_Initialize() loads the frozen
code along with sys and imp and then uses _frozen_importlib._install()
to set builtins.__import__() w/ _frozen_importlib.__import__().
diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index cc22d73..8b94993 100755
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -299,9 +299,8 @@
         elif exc is SyntaxError:
             # A SyntaxError occurred before we could execute the module.
             raise ErrorDuringImport(value.filename, info)
-        elif exc is ImportError and extract_tb(tb)[-1][2]=='safeimport':
-            # The import error occurred directly in this function,
-            # which means there is no such module in the path.
+        elif exc is ImportError and value.name == path:
+            # No such module in the path.
             return None
         else:
             # Some other error occurred during the importing process.