perf report: Set browser mode right before setup_browser()

perf report: Set browser mode right before setup_browser()

There are codes that print messages to the screen between assignment of
the use_browser variable and setup_browser().

But since the GUI browser is not initialized during that period, all
messages fail to show if the user passed the --gtk option to perf as GTK
is not initialized yet.

Reorder the code to assign use_browser variable right before
setup_browser() is called.

Signed-off-by: Seokho Song <0xdevssh@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20171204160244.6332-1-0xdevssh@gmail.com
Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>