perf tools: Remove check for unused PERF_PAGER_IN_USE

PERF_PAGER_IN_USE doesn't seem to be used anywhere, so let's remove it.

This will also make it easier to move pager.c into a separate library.

Signed-off-by: Josh Poimboeuf <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/pager.c

···
 
 int pager_in_use(void)
 {
-	const char *env;
-
-	if (spawned_pager)
-		return 1;
-
-	env = getenv("PERF_PAGER_IN_USE");
-	return env ? perf_config_bool("PERF_PAGER_IN_USE", env) : 0;
+	return spawned_pager;
 }