fixed CL_NextDemo not being called after a drop error or fopen failing

changelog.txt

@@ -25,6 +25,10 @@ chg: with r_backend GL3, depth fade with MSAA now requires GLSL 4.00 at a minimu
 
 chg: with r_backend GL3, alpha to coverage now requires GLSL 4.00 at a minimum
 
+fix: the nextdemo variable wasn't used to start the playback of a new demo when:
+  - a drop error happened during demo playback
+  - the engine failed to open the current demo file
+
 fix: the Linux/FreeBSD client could crash during start-up
 
 fix: with r_backend D3D11, the alpha channel's blend factors now match the original Q3 behavior

code/client/cl_main.cpp

@@ -375,6 +375,7 @@ void CL_PlayDemo_f()
 	CL_WalkDemoExt( demoPath, &fh );
 	if ( fh == 0 ) {
 		Com_Printf( "Couldn't open demo %s\n", demoPath );
+		CL_NextDemo();
 		return;
 	}
 

code/qcommon/common.cpp

@@ -308,10 +308,10 @@ void QDECL Com_ErrorExt( int code, int module, qbool realError, const char *fmt,
 		const qbool demo = CL_DemoPlaying();
 		CL_Disconnect( qtrue );
 		CL_FlushMemory(); // shuts down the VMs and starts them back up
-		if ( realError )
-			CL_ForwardUIError( code == ERR_DROP ? EXT_ERRLEV_DROP : EXT_ERRLEV_DISC, module, com_errorMessage );
-		else if ( demo )
+		if ( demo && *Cvar_VariableString("nextdemo") != '\0' )
 			CL_NextDemo();
+		else if ( realError )
+			CL_ForwardUIError( code == ERR_DROP ? EXT_ERRLEV_DROP : EXT_ERRLEV_DISC, module, com_errorMessage );
 #endif
 		com_errorEntered = qfalse;
 		longjmp (abortframe, -1);