af-packet: terminate on same interface & copyiface

If the interface and copy-iface are same for an af-packet IPS device
setting then fataly exit else it leads to a segfault in later stages.

Bug 5870

(cherry picked from commit d4dd53c95f)

src/runmode-af-packet.c

@@ -201,6 +201,11 @@ static void *ParseAFPConfig(const char *iface)
     if (ConfGetChildValueWithDefault(if_root, if_default, "copy-iface", &out_iface) == 1) {
         if (strlen(out_iface) > 0) {
             aconf->out_iface = out_iface;
+            if (strcmp(iface, out_iface) == 0) {
+                FatalError(SC_ERR_FATAL,
+                        "Invalid config: interface (%s) and copy-iface (%s) can't be the same",
+                        iface, out_iface);
+            }
         }
     }