Create __pycache__ dir when the pyc path is explicitly given

Patch from Arfrever Frehtes Taifersar Arahesis.
diff --git a/Lib/py_compile.py b/Lib/py_compile.py
index 03f2c62..111893e 100644
--- a/Lib/py_compile.py
+++ b/Lib/py_compile.py
@@ -123,11 +123,11 @@
             return
     if cfile is None:
         cfile = imp.cache_from_source(file)
-        try:
-            os.mkdir(os.path.dirname(cfile))
-        except OSError as error:
-            if error.errno != errno.EEXIST:
-                raise
+    try:
+        os.makedirs(os.path.dirname(cfile))
+    except OSError as error:
+        if error.errno != errno.EEXIST:
+            raise
     with open(cfile, 'wb') as fc:
         fc.write(b'\0\0\0\0')
         wr_long(fc, timestamp)