remove superfluous quotes in parameter expansion

[nolange]

as this breaks busybox hush shell.
offending functions can be found with
grep -r '${[^}]"[^}]}'

[centos-ci]

Can one of the admins verify this patch?

[diabonas]

Quotes in patterns are actually required (according to POSIX) if the variable contains special pattern characters like * or \, try e.g.

i='a\c'; j='\'; echo "${i%$j*}"

vs.

i='a\c'; j='\'; echo "${i%"$j"*}"

Furthermore I couldn't find any issues with using quotes in parameter expansions with a recent busybox hush build. Since this actually breaks unlocking encrypted partitions with shells like bash, dash and ash, I suggest reintroducing variable quoting at least in patterns, see #794.