RFR: 8305963: Typo in java.security.Security.getProperty

[Kevin Driver]

Fix type-o and update returns message.

-------------

Commit messages:
 - JDK-8305963 fix type-o and update returns message

Changes: https://git.openjdk.org/jdk/pull/13729/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13729&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305963
  Stats: 4 lines in 1 file changed: 1 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/13729.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13729/head:pull/13729

PR: https://git.openjdk.org/jdk/pull/13729