perf report: Fix some option handling on --stdio

There's a bug that perf report sometimes ignore some options on --stdio
output.  This bug is triggered only if a related config variable is set.
For example, let's assume we have a following config file.

  $ cat ~/.perfconfig
  [call-graph]
    print-type = graph
  [hist]
    percentage = absolute

Then, following perf config will not honor some options.

  $ perf record -ag sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.199 MB perf.data (77 samples) ]

  $ perf report -g none --stdio
  # To display the perf.data header info, please use --header/--header-only options.
  #
  # Samples: 77  of event 'cycles'
  # Event count (approx.): 25425383
  #
  # Overhead  Command          Shared Object            Symbol
  # ........  ...............  .......................  ..............
  #
      16.34%  swapper          [kernel.vmlinux]         [k] intel_idle
                      |
                      ---intel_idle
                         cpuidle_enter_state
                         cpuidle_enter
                         cpu_startup_entry
   ...

With '-g none' option, it should not show callchains, but it still shows
callchains.  However it works as expected on --tui output.

Similarly, '--percentage relative' option is not work and still shows a
absolute percentage values.

Looking at the source, I found that those setting were overwritten by
config variables when setup_pager() called.  The setup_pager() is to
start a pager process so that it can manage long lines of output on the
stdio mode.  But as it calls the perf_config() after parsing arguments,
the settings were overwritten regardless of command line options.

The reason it calls perf_config() is to find the 'pager_program' which
might be set by a config variable, I guess.  However current perf code
does not provide the config variable for it, so it's just meaningless
IMHO.  Eliminating the call makes the option working as expected.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Taeung Song <treeze.taeung@gmail.com>
Link: http://lkml.kernel.org/r/1431529406-6762-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/cache.h

@@ -30,7 +30,6 @@ extern const char *perf_config_dirname(const char *, const char *);
 
 /* pager.c */
 extern void setup_pager(void);
-extern const char *pager_program;
 extern int pager_in_use(void);
 extern int pager_use_color;
 

tools/perf/util/environment.c

@@ -5,5 +5,4 @@
  */
 #include "cache.h"
 
-const char *pager_program;
 int pager_use_color = 1;

tools/perf/util/pager.c

@@ -50,11 +50,6 @@ void setup_pager(void)
 
 	if (!isatty(1))
 		return;
-	if (!pager) {
-		if (!pager_program)
-			perf_config(perf_default_config, NULL);
-		pager = pager_program;
-	}
 	if (!pager)
 		pager = getenv("PAGER");
 	if (!(pager || access("/usr/bin/pager", X_OK)))