libc/eglibc: fix installed scripts

Like rev 2002, eglibc installs some bash scripts, but use the path to the
buildtool bash as the interpreter (on the shebang line). This is only a
symlink to the real bash, and thus is not available at runtime.

Fix that by assuming that shell on the target *will* be /bin/bash.

Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>

 This is NOT the official version of dialog.  This version has been

 significantly modified from the original.  It is for use by the Linux

 kernel configuration script.  Please do not bother Savio Lam with 

 questions about this program.