DCAP Error

Any ideas why the DCAP sample isn't working out of the box?

I'm using with the recommended docker image. Maybe this doesn't have all the binaries needed to run this same?

```
root@7006db9d90eb:~/sgx/samplecode/dcap-pckretrieval# make
Finished release [optimized] target(s) in 0.00s
Cargo => bin/libdcap_quoteprov.so.1
Compiling PCKIDRetrievalTool v1.0.0 (/root/sgx/samplecode/dcap-pckretrieval/app)
error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
--> src/main.rs:158:14
|
158 | let _l = libloading::Library::new("./libdcap_quoteprov.so.1").unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function
|
= note: consult the function's documentation for information on how to avoid undefined behavior

error: aborting due to previous error

For more information about this error, try `rustc --explain E0133`.
error: could not compile `PCKIDRetrievalTool`
```

Start with samplecode/dcap-pckretrieval/app/src/main.rs at line 158 and reproduce the failure with make in the recommended Docker image. Check whether the image provides the binaries needed by the DCAP sample and determine what prevents the sample from building out of the box. Done means the sample builds successfully in that image.

Written by the indexing model from the issue text.