[obv] Code cleanup: Move print_command_1 expr variable scope

[Simon Marchi]

Hi Jan,

I think this patch is wrong. Starting with that commit (f30d5c7),
some tests (e.g. mi-break.exp) started to fail for me, because
of gdb segfaulting. Backtrace here: http://paste.ubuntu.com/10690836/

The address of expr is passed to the cleanup. When the cleanup is ran,
expr is no longer in scope, so what is at that address is probably not
safe to use anymore. That's my guess.

Simon