RFR: JDK-6676643: Improve current C_GetAttributeValue native implementation [v4]

[Valerie Peng]

> Anyone can help review this somewhat trivial fix? The main change is inside src/jdk.crypto.cryptoki/share/native/libj2pkcs11/p11_objmgmt.c. This is to help better troubleshooting by reporting the type of unavailable attributes in PKCS11 exception message when C_GetAttributeValue(...) call failed. The java file changes are just cleanup for consolidating the CKR_* constants definition into PKCS11Exception class.
> 
> Thanks,
> Valerie

Valerie Peng has updated the pull request incrementally with one additional commit since the last revision:

  Use the final field "value" directly and remove value() method.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3709/files
  - new: https://git.openjdk.java.net/jdk/pull/3709/files/c08f62f7..057c3dfc

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3709&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3709&range=02-03

  Stats: 19 lines in 1 file changed: 0 ins; 3 del; 16 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3709.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3709/head:pull/3709

PR: https://git.openjdk.java.net/jdk/pull/3709