releasing on Linux is ~broken

[exterkamp]

Releasing on Linux isn't perfect b/c some sed commands don't work...

#roll-to-devtools.sh
sed -i '' -e "s/Version:.*/Version: $VERSION/g" "$tests_dir"/*-expected.txt

#prepare-commit.sh
sed -i '' "s/$NEEDLE/$REPLACEMENT/g" package.json clients/extension/manifest.json

Removing the '' works, but this might break mac.

[connorjclark]

dupe #9857