Fix failure to build from source when compiling the crash utility
with gcc-4.9.  Without the patch, the crash utility build generates
the following error:

  In file included from opncls.c:26:0:
  opncls.c: In function 'bfd_fopen':
  bfd.h:529:65: error: right-hand operand of comma expression has no effect [-Werror=unused-value]
  #define bfd_set_cacheable(abfd,bool) (((abfd)->cacheable = bool), TRUE)
                                                                  ^
  opncls.c:263:5: note: in expansion of macro 'bfd_set_cacheable' bfd_set_cacheable (nbfd, TRUE);

  cc1: all warnings being treated as errors

(anderson@redhat.com, anatol.pomozov@gmail.com)