libext2fs: Move test code for csum.c inline instead of in a separate file

Move the test code which is used to build the tst_csum progam from
tst_csum into csum.c under an #ifdef DEBUG to simplify things and to
avoid compile problems caused by not having a prototype for
ext2fs_group_desc_csum().

Addresses-Sourceforge-Bug: #2484331

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