* baseboards/basic-sid.exp, baseboards/basic-sim.exp,
        baseboards/i386-sid.exp, baseboards/mt-sid.exp,
        baseboards/sh-sid.exp, config/adb.exp, config/gdb-comm.exp,
        config/gdb_stub.exp, config/sim.exp, config/unix.exp,
        config/vxworks.exp, lib/dejagnu.exp, lib/dg.exp,
        lib/framework.exp, lib/kermit.exp, lib/libgloss.exp,
        lib/remote.exp, lib/rsh.exp, lib/target.exp, lib/tip.exp,
        lib/utils.exp, testsuite/lib/libsup.exp,
        testsuite/runtest.all/options.exp,: Remove unnecessary braces
        around variable expansions.