smcposix: pass unicode as first argument to array.array

This is an instance where we can safely convert the first argument, rest are
the cases except one where we are using 'c' which is not there in Python 3. So
that needs to be handled differently. This will help in making `hg help` run on
Python 3.

mercurial/scmposix.py

@@ -66,7 +66,7 b' def termsize(ui):'
             if not os.isatty(fd):
                 continue
             arri = fcntl.ioctl(fd, TIOCGWINSZ, '\0' * 8)
-            height, width = array.array('h', arri)[:2]
+            height, width = array.array(r'h', arri)[:2]
             if width > 0 and height > 0:
                 return width, height
         except ValueError: