perf tools: Fix line number in the config file error message

If we fail to parse the config file within the callback function,
the line number counter 'could be' already on the next line.

This results in wrong line number report like:

  $ cat ~/.perfconfig
  [call-graph]
          sort-key = krava
  $ perf record ls
  Fatal: bad config file line 3 in /home/jolsa/.perfconfig

Fixing this by saving the current line number for this case.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Milian Wolff <mail@milianw.de>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20140923115656.GC2979@krava.brq.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>