Fixup commit a8177b8cc3300fd64eef0acb7397be15fb0e0b4c

Per https://github.com/D-Programming-Language/phobos/commit/a8177b8cc3300fd64eef0acb7397be15fb0e0b4c#commitcomment-4991972 :
"nothrow" was superfluous
Merge pull request #1839 from monarchdodra/cycle3

Fixup commit a8177b8cc3300fd64eef0acb7397be15fb0e0b4c