Fix quoting of local variable assignments throughout.

Fix quoting of local variable assignments throughout.

When you assign a variable directly (e.g., `FOO=bar`), you don't need
to quote the RHS, because the shell doesn't do expansion in that
case.  But when you declare and assign a variable (e.g., `local
foo=bar`), you *do* potentially need to quote it, because `local` is a
command and all the normal expansion rules for running commands
applies.