suricata: remove instance from ParseCommandLine

We want to be able to call ParseCommandLine from library users, but
currently library users don't have access to the `suricata` instance
type. Since this var is used other places as a global, use the global
one in ParseCommandLine as well.

Not ideal, but isolating SCInstance to a non-global will be another
challenge on its own.

src/suricata.c

@@ -1312,8 +1312,9 @@ static bool IsLogDirectoryWritable(const char* str)
 
 extern int g_skip_prefilter;
 
-static TmEcode ParseCommandLine(int argc, char** argv, SCInstance *suri)
+static TmEcode ParseCommandLine(int argc, char **argv)
 {
+    SCInstance *suri = &suricata;
     int opt;
 
     int dump_config = 0;
@@ -2899,7 +2900,7 @@ void SuricataPreInit(const char *progname)
 
 void SuricataInit(int argc, char **argv)
 {
-    if (ParseCommandLine(argc, argv, &suricata) != TM_ECODE_OK) {
+    if (ParseCommandLine(argc, argv) != TM_ECODE_OK) {
         exit(EXIT_FAILURE);
     }