Use SHA1 hash for kernel cache key to support Linux in FIPS-compliant mode - #5988

In [8]: %timeit hashlib.md5(a).hexdigest()
5.15 µs ± 1.85 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

In [9]: %timeit hashlib.sha256(a).hexdigest()
2.29 µs ± 1.05 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

In [10]: %timeit hashlib.sha1(a).hexdigest()
2.15 µs ± 0.303 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

In [11]: timeit('hashlib.md5(a).hexdigest()')
4.6 ns ± 0.0011 ns per loop (mean ± std. dev. of 7 runs, 100000000 loops each)

In [12]: timeit('hashlib.sha1(a).hexdigest()')
4.61 ns ± 0.0055 ns per loop (mean ± std. dev. of 7 runs, 100000000 loops each)

In [13]: timeit('hashlib.sha256(a).hexdigest()')
4.79 ns ± 0.396 ns per loop (mean ± std. dev. of 7 runs, 100000000 loops each)