no_std usage broken

[sleffler]

Commit 4ef07e25a8b08153d527db84dd7f02d398ea1040 broke no_std support. This in turn broke my no_std usage of the hashbrown crate because I use ahash with the compile-time-rng feature which brings in const-random. (ahash pins const-random to 0.1.12 but because the maintainers yanked that version it appears the dep floats to the latest rev.)

[tkaitchuck]

Fixed in 0.1.17