libselinux: set free'd data to NULL #139

Job	Run time
build (gcc, 3.12, 3.3)	1m 36s
build (gcc, 3.12, 3.3, test-flags-override)	1m 22s
build (gcc, 3.12, 3.3, test-debug)	1m 26s
build (gcc, 3.12, 3.3, linker-bfd)	1m 33s
build (gcc, 3.12, 3.3, linker-gold)	1m 30s
build (gcc, 3.11, 3.3)	1m 34s
build (gcc, 3.10, 3.3)	1m 35s
build (gcc, 3.9, 3.3)	2m 25s
build (gcc, 3.8, 3.3)	1m 41s
build (gcc, 3.7, 3.3)	1m 53s
build (gcc, pypy3.7, 3.3)	2m 6s
build (gcc, 3.12, 3.2)	2m 1s
build (gcc, 3.12, 3.1)	2m 6s
build (gcc, 3.12, 3.0)	2m 10s
build (gcc, 3.12, 2.7)	1m 45s
build (gcc, 3.12, 2.6)	2m 7s
build (gcc, 3.12, 2.5)	1m 43s
build (clang, 3.12, 3.3)	1m 43s
build (clang, 3.12, 3.3, test-flags-override)	1m 27s
build (clang, 3.12, 3.3, test-debug)	1m 24s
build (clang, 3.11, 3.3)	1m 36s
build (clang, 3.10, 3.3)	1m 42s
build (clang, 3.9, 3.3)	1m 34s
build (clang, 3.8, 3.3)	2m 17s
build (clang, 3.7, 3.3)	1m 42s
build (clang, pypy3.7, 3.3)	2m 6s
build (clang, 3.12, 3.2)	1m 46s
build (clang, 3.12, 3.1)	1m 43s
build (clang, 3.12, 3.0)	1m 52s
build (clang, 3.12, 2.7)	1m 53s
build (clang, 3.12, 2.6)	2m 2s
build (clang, 3.12, 2.5)	1m 48s
build (gcc, 3.12, 3.3, sanitizers)	1m 59s
	59m 7s

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