ts_31_102: Use perror() instead of poutput() for errors

This adds colorization and ensures they go to stderr and not stdout

Change-Id: I34b8f974b4ff13002679c4700bdf604db7d7f3cd
diff --git a/pySim/ts_31_102.py b/pySim/ts_31_102.py
index ce32b20..7fcb08e 100644
--- a/pySim/ts_31_102.py
+++ b/pySim/ts_31_102.py
@@ -620,9 +620,9 @@
                     if exists != should_exist:
                         num_problems += 1
                         if exists:
-                            cmd.poutput("  ERROR: File %s is selectable but should not!" % f)
+                            cmd.perror("  ERROR: File %s is selectable but should not!" % f)
                         else:
-                            cmd.poutput("  ERROR: File %s is not selectable (%s) but should!" %  (f, sw))
+                            cmd.perror("  ERROR: File %s is not selectable (%s) but should!" %  (f, sw))
         finally:
             # re-select the EF.UST
             cmd.card._scc.select_file(self.fid)
@@ -655,11 +655,11 @@
             active_services = selected_file.get_active_services(self._cmd)
             # Service n°46 can only be declared "available" if service n°45 is declared "available"
             if 46 in active_services and not 45 in active_services:
-                self._cmd.poutput("ERROR: Service 46 available, but it requires Service 45")
+                self._cmd.perror("ERROR: Service 46 available, but it requires Service 45")
                 num_problems += 1
             # Service n°125 shall only be taken into account if Service n°124 is declared "available"
             if 125 in active_services and not 124 in active_services:
-                self._cmd.poutput("ERROR: Service 125 is ignored as Service 124 not available")
+                self._cmd.perror("ERROR: Service 125 is ignored as Service 124 not available")
                 num_problems += 1
             # Service n°95, n°99 and n°115 shall not be declared "available" if an ISIM application is present on the UICC
             non_isim_services = [95, 99, 115]
@@ -667,7 +667,7 @@
             if 'ADF.ISIM' in app_names:
                 for s in non_isim_services:
                     if s in active_services:
-                        self._cmd.poutput("ERROR: Service %u shall not be available as ISIM application is present" % s)
+                        self._cmd.perror("ERROR: Service %u shall not be available as ISIM application is present" % s)
                         num_problems += 1
             self._cmd.poutput("===> %u service / file inconsistencies detected" % num_problems)