shells/fish: patch upstream issue #5453

This change fixes a segfault that would happen from operations like
'printf "%f" 7.0'. Also, this change removes Python as a runtime
dependency. That was supposed to have been done in r488840, but there was a
typo.

https://github.com/fish-shell/fish-shell/issues/5453

Reported by: Mahmoud Al-Qudsi <mqudsi@neosmart.net>
MFH: 2019Q1