Revert "qemu: support notify sockets"

This reverts commit 3910e65.

See #313 (comment)

lib/runners/qemu.nix

@@ -146,7 +146,6 @@ let
     then "console=ttyAMA0"
     else "";
 
-  supportsNotifySocket = vsock.cid != null;
 
 in
 lib.warnIf (mem == 2048) ''
@@ -155,16 +154,7 @@ lib.warnIf (mem == 2048) ''
   <https://github.com/astro/microvm.nix/issues/171>
 ''
 {
-  inherit tapMultiQueue supportsNotifySocket;
-
-  preStart = ''
-    ${microvmConfig.preStart}
-  '' + lib.optionalString supportsNotifySocket ''
-    # Start socat to forward systemd notify socket over vsock
-    if [ -n "''${NOTIFY_SOCKET-}" ]; then
-      ${pkgs.socat}/bin/socat VSOCK-LISTEN:8888,fork UNIX-SENDTO:$NOTIFY_SOCKET &
-    fi
-  '';
+  inherit tapMultiQueue;
 
   command = lib.escapeShellArgs (
     [
@@ -310,11 +300,6 @@ lib.warnIf (mem == 2048) ''
     lib.optionals (vsock.cid != null) [
       "-device"
       "vhost-vsock-${devType},guest-cid=${toString vsock.cid}"
-      # We are *supposed* to use SMBIOS here. But somehow, no matter how much I
-      # tried, SMBIOS Type 11 entries simply don't work. It looks like it might
-      # be broken on QEMU side. Why? I don't know.
-      "-fw_cfg"
-      "name=opt/io.systemd.credentials/vmm.notify_socket,string=vsock-stream:2:8888"
     ]
     ++
     extraArgs