RFR: 8283217: Leak FcObjectSet in getFontConfigLocations() in fontpath.c [v2]

[Zhengyu Gu]

> Please review this small patch to fix leaking of `FcObjectSet` in  `getFontConfigLocations()`
> 
> 
> Test:
> - [x]  jdk_2d

Zhengyu Gu has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into JDK-8283217-destroy-FcObjectSet
 - v0

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7826/files
  - new: https://git.openjdk.java.net/jdk/pull/7826/files/6caca241..754e33b5

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7826&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7826&range=00-01

  Stats: 587 lines in 28 files changed: 374 ins; 73 del; 140 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7826.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7826/head:pull/7826

PR: https://git.openjdk.java.net/jdk/pull/7826