vhost_user_net: Rely on upstream vhost-user-backend crate

Instead of relying on the local version of vhost-user-backend, this
patch allows the block backend implementation to rely on the upstream
version of the crate from rust-vmm.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

Cargo.lock

@@ -1122,6 +1122,20 @@ dependencies = [
  "vmm-sys-util",
 ]
 
+[[package]]
+name = "vhost-user-backend"
+version = "0.1.0"
+source = "git+https://github.com/rust-vmm/vhost-user-backend?branch=main#bbc892ba4526bdf8101252f7aa51832d1f2eeabd"
+dependencies = [
+ "libc",
+ "log",
+ "vhost",
+ "virtio-bindings",
+ "virtio-queue",
+ "vm-memory",
+ "vmm-sys-util",
+]
+
 [[package]]
 name = "vhost_user_backend"
 version = "0.1.0"
@@ -1150,7 +1164,7 @@ dependencies = [
  "option_parser",
  "qcow",
  "vhost",
- "vhost-user-backend",
+ "vhost-user-backend 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "virtio-bindings",
  "vm-memory",
  "vmm-sys-util",
@@ -1168,7 +1182,7 @@ dependencies = [
  "net_util",
  "option_parser",
  "vhost",
- "vhost_user_backend",
+ "vhost-user-backend 0.1.0 (git+https://github.com/rust-vmm/vhost-user-backend?branch=main)",
  "virtio-bindings",
  "vm-memory",
  "vmm-sys-util",