bpftool: fix indendation in bash-completion/bpftool

Fix misaligned default case branch for `prog dump` sub-command.
Reported-by: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Yonghong Song <yhs@fb.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>