crecord: ensure that curses is False if not imported

This provides no functional change but makes the next two patches easier to
review.

mercurial/crecord.py

@@ -43,8 +43,9 b' except ImportError:'
         import wcurses as curses
         curses.error
     except ImportError:
-        # wcurses is not shipped on Windows by default
-        pass
+        # wcurses is not shipped on Windows by default, or python is not
+        # compiled with curses
+        curses = False
 
 try:
     curses