fixup! X509_add_cert(): prevent double free on X509_up_ref() failure #963

Job	Run time
compiler (gcc-7, ubuntu-20.04)	7m 30s
compiler (gcc-8, ubuntu-20.04)	7m 33s
compiler (gcc-9, ubuntu-20.04)	8m 0s
compiler (gcc-10, ubuntu-20.04)	7m 33s
compiler (gcc-11, ubuntu-22.04)	7m 37s
compiler (gcc-12, ubuntu-22.04)	8m 16s
compiler (gcc-13, ubuntu-22.04, ubuntu-toolchain-r/test)	9m 23s
compiler (clang-6.0, ubuntu-20.04)	7m 45s
compiler (clang-7, ubuntu-20.04)	7m 42s
compiler (clang-8, ubuntu-20.04)	8m 3s
compiler (clang-9, ubuntu-20.04)	8m 2s
compiler (clang-10, ubuntu-20.04)	7m 38s
compiler (clang-11, ubuntu-20.04)	10m 1s
compiler (clang-12, ubuntu-20.04)	7m 41s
compiler (clang-13, ubuntu-22.04)	8m 6s
compiler (clang-14, ubuntu-22.04)	9m 29s
compiler (clang-15, ubuntu-22.04, jammy)	8m 5s
compiler (clang-16, ubuntu-22.04, jammy)	8m 11s
	2h 26m 35s

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