Drop qemu-objects.h from modules that don't require it

Previous commits dropped most qobjects usage from qemu modules
(now they are a low level interface used by the QAPI). However,
some modules still include the qemu-objects.h header file.

This commit drops qemu-objects.h from some of those modules
and includes qjson.h instead, which is what they actually need.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

block.c

@@ -27,7 +27,7 @@
 #include "monitor.h"
 #include "block_int.h"
 #include "module.h"
-#include "qemu-objects.h"
+#include "qjson.h"
 #include "qemu-coroutine.h"
 #include "qmp-commands.h"
 

error.c

@@ -12,8 +12,9 @@
 
 #include "qemu-common.h"
 #include "error.h"
+#include "qjson.h"
+#include "qdict.h"
 #include "error_int.h"
-#include "qemu-objects.h"
 #include "qerror.h"
 
 struct Error

vl.c

@@ -143,9 +143,9 @@ int main(int argc, char **argv)
 #include "audio/audio.h"
 #include "migration.h"
 #include "kvm.h"
+#include "qjson.h"
 #include "qemu-option.h"
 #include "qemu-config.h"
-#include "qemu-objects.h"
 #include "qemu-options.h"
 #include "qmp-commands.h"
 #include "main-loop.h"