Remove the union in evsel so that the database id and priv pointer can
be used simultainously without conflicting and crashing.

Detailed Description for the fixed bug follows:

perf script crashes with a segmentation fault on user space tool version
4.5.rc7.ge2857b when using the python database export API. It works
properly in 4.4 and prior versions.

the crash fist appeared in:

cfc8874a ("perf script: Process cpu/threads maps")

How to reproduce the bug:

Remove any temporary files left over from a previous crash (if you have
already attemped to reproduce the bug):

  $ rm -r test_db-perf-data
  $ dropdb test_db

  $ perf record timeout 1 yes >/dev/null
  $ perf script -s scripts/python/export-to-postgresql.py test_db

  Stack Trace:
  Program received signal SIGSEGV, Segmentation fault.
  __GI___libc_free (mem=0x1) at malloc.c:2929
  2929	malloc.c: No such file or directory.
  (gdb) bt
    at util/stat.c:122
    argv=<optimized out>, prefix=<optimized out>) at builtin-script.c:2231
    argc=argc@entry=4, argv=argv@entry=0x7fffffffdf70) at perf.c:390
    at perf.c:451
Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: cfc8874a ("perf script: Process cpu/threads maps")
Link: http://lkml.kernel.org/r/1457500314-8912-1-git-send-email-cphlipot0@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>