fix initialization of invalid fds

With Rust 1.52.1 we can no longer initialize invalid fd 2 by using -1 as
the value because there is an assert in the from_raw_fd function that
checks for that value. We can use -2 instead.

Signed-off-by: Andreea Florescu <[email protected]>

Author: andreeaflorescu

src/ioctls/system.rs

@@ -718,7 +718,7 @@ mod tests {
         let badf_errno = libc::EBADF;
 
         let faulty_kvm = Kvm {
-            kvm: unsafe { File::from_raw_fd(-1) },
+            kvm: unsafe { File::from_raw_fd(-2) },
         };
 
         assert_eq!(

src/ioctls/vcpu.rs

@@ -1969,7 +1969,7 @@ mod tests {
         let badf_errno = libc::EBADF;
 
         let faulty_vcpu_fd = VcpuFd {
-            vcpu: unsafe { File::from_raw_fd(-1) },
+            vcpu: unsafe { File::from_raw_fd(-2) },
             kvm_run_ptr: KvmRunWrapper {
                 kvm_run_ptr: mmap_anonymous(10),
                 mmap_size: 10,

src/ioctls/vm.rs

@@ -1633,7 +1633,7 @@ mod tests {
         let badf_errno = libc::EBADF;
 
         let faulty_vm_fd = VmFd {
-            vm: unsafe { File::from_raw_fd(-1) },
+            vm: unsafe { File::from_raw_fd(-2) },
             run_size: 0,
         };