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

[Zhengyu Gu]

Please review this small patch to fix leaking of `FcObjectSet` in  `getFontConfigLocations()`


Test:
- [x]  jdk_2d

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Commit messages:
 - v0

Changes: https://git.openjdk.java.net/jdk/pull/7826/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7826&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283217
  Stats: 6 lines in 1 file changed: 6 ins; 0 del; 0 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