Fix potential memory leak in ZstdCompressor.compress()
Fix potential memory leak in ZstdCompressor.compress()

Would only happen if ZSTD_createCCtx() failed, which should be
rare since it takes no arguments and basically performs an
allocation.
indygreg/python-zstandard,terrelln/python-zstandard,indygreg/python-zstandard,indygreg/python-zstandard,terrelln/python-zstandard,indygreg/python-zstandard,terrelln/python-zstandard,terrelln/python-zstandard