*.sh: use consistent indentation

Almost all of the shell scripts in the repository use tabs for
indentation (or have no indentation at all):

    $ git grep -Il '^\t' -- '*.sh' | wc -l
    19
    $ git grep -Il '^ ' -- '*.sh' | wc -l
    5
    $ git grep -IL '^[ \t]' -- '*.sh' | wc -l
    25

So do the same in the few shell scripts that currently use spaces for
indentation.

Except for the following file:

* platform/rpm/mkrpm.sh

Not sure if it's following a packaging-specific scheme, so just fix the
one indentation inconsistency in it and otherwise leave it as is for
now.

Command used to search for shell scripts using spaces for indentation:

    $ git grep -In '^ ' -- '*.sh'

0 files changed, 0 insertions, 0 deletions