Merge some file writing extension checks from OpenJK.

Thanks Ensiform.
https://github.com/JACoders/OpenJK/commit/05928a57f9e4aae15a3bd0
https://github.com/JACoders/OpenJK/commit/ef124fd0fc48af164581176
void Com_StartupVariable( const char *match ) {
	int		i;
	char	*s;

	for (i=0 ; i < com_numConsoleLines ; i++) {
		Cmd_TokenizeString( com_consoleLines[i] );
		if ( strcmp( Cmd_Argv(0), "set" ) ) {
			continue;
		}

		s = Cmd_Argv(1);
		
		if(!match || !strcmp(s, match))
		{
			if(Cvar_Flags(s) == CVAR_NONEXISTENT)
				Cvar_Get(s, Cmd_ArgsFrom(2), CVAR_USER_CREATED);
			else
				Cvar_Set2(s, Cmd_ArgsFrom(2), qfalse);
		}
	}
}

void Com_StartupVariable( const char *match ) {
	int		i;
	char	*s;

	for (i=0 ; i < com_numConsoleLines ; i++) {
		Cmd_TokenizeString( com_consoleLines[i] );
		if ( strcmp( Cmd_Argv(0), "set" ) ) {
			continue;
		}

		s = Cmd_Argv(1);
		
		if(!match || !strcmp(s, match))
		{
			if(Cvar_Flags(s) == CVAR_NONEXISTENT)
				Cvar_Get(s, Cmd_ArgsFrom(2), CVAR_USER_CREATED);
			else
				Cvar_Set2(s, Cmd_ArgsFrom(2), qfalse);
		}
	}
}
