[RFC 0/3] Get rid of var_integer in CLI

[Yao Qi]

Hello,
This patch set can be regarded as the preparation for this series,

  [RFC 0/3] New var_types var_zuinteger_unlimited
  http://sourceware.org/ml/gdb-patches/2012-08/msg00020.html

In this version, we try to get rid of 'var_integer' first and it
will not be used except in Python API.  As the meaning of var_integer
is strange, we'd better not use it any more (but we should keep it
there for Python API).  What do you think?

Regression tested on x86_64-linux.