Remove expr use from ceylon sh script
Remove expr use from ceylon sh script

I thought ${var#prefix} was a Bashism, but it's actually part of POSIX,
and supported by Bash, Dash, and Mac's sh. So this saves us at least one
spawned process per ceylon invocation, and two on shells where [ is a
builtin (Bash, Dash).

gijsleussink/ceylon,gijsleussink/ceylon,gijsleussink/ceylon,gijsleussink/ceylon,gijsleussink/ceylon