misc: remove once_cell; superseded by std::*

We now have types in the Rust standard library.
Dropping the dependency.

I found this by using the `clippy::pedantic` group.

Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com

fuzz/Cargo.lock

@@ -217,7 +217,6 @@ dependencies = [
  "micro_http",
  "mshv-bindings",
  "net_util",
- "once_cell",
  "seccompiler",
  "virtio-devices",
  "virtio-queue",
@@ -362,7 +361,6 @@ version = "0.1.0"
 dependencies = [
  "flume",
  "libc",
- "once_cell",
  "serde",
  "serde_json",
 ]
@@ -1089,7 +1087,6 @@ version = "0.1.0"
 dependencies = [
  "libc",
  "log",
- "once_cell",
  "serde",
  "serde_json",
 ]
@@ -1316,7 +1313,6 @@ dependencies = [
  "log",
  "micro_http",
  "net_util",
- "once_cell",
  "option_parser",
  "pci",
  "rate_limiter",