e2fsck: Detect recursive loops in @-expansions

The Turkish translation has a bug in it where it has the translation
of "E@e '%Dn' in %p (%i)" to "E@E".  This causes @E to be expanded at
@E, recursively, forever, until the stack fills up e2fsck core dumps.

Fix it by stopping after a recursive depth of 10, which is far more
than we need.

Addresses-Sourceforge-Bug: 1646081

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
3 files changed