Initialize yet another variable to silence GCC warning from last-but-one commit
    
    Yet another BuildBot e-mail, yet another breakage on RHEL-7.1 s390x
    (which uses an older GCC).  This time,
    solib-svr4.c:solib_event_probe_action has the probe_argc variable,
    which is now inside a TRY..CATCH and therefore needs to be
    initialized.  Pushed as obvious.
    
    gdb/ChangeLog:
    2015-09-01  Sergio Durigan Junior  <sergiodj@redhat.com>
    
    	* solib-svr4.c (solib_event_probe_action): Initialize 'probe_argc'
    	as zero.