tests: Use vmm_sys_util::tempfile::Tempfile in integration tests

This removes the requirement for an extra crate and simplifies the
dependency chain.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

Cargo.lock

@@ -233,7 +233,6 @@ dependencies = [
  "signal-hook",
  "ssh2",
  "tempdir",
- "tempfile",
  "thiserror",
  "vm-memory",
  "vmm",
@@ -760,7 +759,7 @@ dependencies = [
  "cfg-if 0.1.10",
  "cloudabi",
  "libc",
- "redox_syscall 0.1.57",
+ "redox_syscall",
  "smallvec",
  "winapi 0.3.9",
 ]
@@ -1004,15 +1003,6 @@ version = "0.1.57"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "41cc0f7e4d5d4544e8861606a285bb08d3e70712ccc7d2b84d7c0ccfaf4b05ce"
 
-[[package]]
-name = "redox_syscall"
-version = "0.2.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05ec8ca9416c5ea37062b502703cd7fcb207736bc294f6e0cf367ac6fc234570"
-dependencies = [
- "bitflags 1.2.1",
-]
-
 [[package]]
 name = "redox_users"
 version = "0.3.5"
@@ -1020,7 +1010,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "de0737333e7a9502c789a36d7c7fa6092a49895d4faa31ca5df163857ded2e9d"
 dependencies = [
  "getrandom 0.1.16",
- "redox_syscall 0.1.57",
+ "redox_syscall",
  "rust-argon2",
 ]
 
@@ -1301,20 +1291,6 @@ dependencies = [
  "remove_dir_all",
 ]
 
-[[package]]
-name = "tempfile"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dac1c663cfc93810f88aed9b8941d48cabf856a1b111c29a40439018d870eb22"
-dependencies = [
- "cfg-if 1.0.0",
- "libc",
- "rand 0.8.3",
- "redox_syscall 0.2.4",
- "remove_dir_all",
- "winapi 0.3.9",
-]
-
 [[package]]
 name = "term"
 version = "0.4.6"