runmode: remove unused variable.

default_mode_auto is not used anymore and can be removed.

src/runmode-af-packet.c

@@ -57,7 +57,6 @@
 
 extern int max_pending_packets;
 
-static const char *default_mode_auto = NULL;
 static const char *default_mode_autofp = NULL;
 
 const char *RunModeAFPGetDefaultMode(void)
@@ -67,7 +66,6 @@ const char *RunModeAFPGetDefaultMode(void)
 
 void RunModeIdsAFPRegister(void)
 {
-    default_mode_auto = "autofp";
     RunModeRegisterNewRunMode(RUNMODE_AFP_DEV, "auto",
                               "Multi threaded af-packet mode",
                               RunModeIdsAFPAuto);

src/runmode-pfring.c

@@ -37,7 +37,6 @@
 #include "util-runmodes.h"
 #include "util-device.h"
 
-static const char *default_mode_auto = NULL;
 static const char *default_mode_autofp = NULL;
 
 
@@ -55,7 +54,6 @@ const char *RunModeIdsPfringGetDefaultMode(void)
 
 void RunModeIdsPfringRegister(void)
 {
-    default_mode_auto = "autofp";
     RunModeRegisterNewRunMode(RUNMODE_PFRING, "auto",
                               "Multi threaded pfring mode",
                               RunModeIdsPfringAuto);