perf tui: Fix last use_browser problem related to .perfconfig

When we moved to using ~/.perfconfig to set the value of use_browser,
it changed from a boolean to an int so that the convention used for
use_pager was followed.

That convention is:

-1: unspecified, that is what use_{browser,pager} is initialized
0: Don't use the browser (should be TUI), because was explicitely
set to 0/off/false on ~/.perfconfig [tui] cmd =, or because
we're redirecting the stdout to a file or piping it to some
other command (!isatty()).
1: Use the TUI

Some code was not properly audited and continued testing it as a
boolean, this seems to be the last one.

Reported-by: Frédéric Weisbecker <[e-mail]>
Tested-by: Frédéric Weisbecker <[e-mail]>
Cc: Frédéric Weisbecker <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Cc: Tom Zanussi <[e-mail]>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/debug.c

···
 
 	if (verbose >= level) {
 		va_start(args, fmt);
-		if (use_browser)
+		if (use_browser > 0)
 			ret = browser__show_help(fmt, args);
 		else
 			ret = vfprintf(stderr, fmt, args);