Build issues

Created by: Johann-S

Due to the merged of https://github.com/twbs/bootstrap/pull/22045

they are few errors, on Travis see : - https://travis-ci.org/twbs/bootstrap/jobs/223876338#L312 - https://travis-ci.org/twbs/bootstrap/jobs/223876309#L303

And on my computer (Win10) js-compile-bundle don't work because it failed here : shx sed 's/^(import|export).*//'

I changed this part of this task into to make it works :

shx sed \"s/^(import|export).*//\"

/CC @bardiharborow