global: convert indentation-TABs to spaces

Transformed via this shell code:
t=$'\t'
git ls-files \
  | grep -vE '(^|/)((GNU)?[Mm]akefile|ChangeLog)|\.(am|mk)$' \
  | grep -vE 'tests/pr/|help2man' \
  | xargs grep -lE "^ *$t" \
  | xargs perl -MText::Tabs -ni -le \
    '$m=/^( *\t[ \t]*)(.*)/; print $m ? expand($1) . $2 : $_'

tests/chgrp/basic

@@ -108,7 +108,7 @@ test "`ls -C -c -t f g`" = 'f  g' || \
       *darwin7.9.*|*darwin8.*)
         echo ignoring known MacOS X-specific chgrp failure 1>&2 ;;
       *) echo $host_triplet: no-change chgrp failed to update ctime 1>&2;
-	    fail=1 ;;
+            fail=1 ;;
     esac
   }