Fix EOF check in kadm5.acl line processing

Fix EOF check in kadm5.acl line processing

On platforms where the char type is unsigned, the check for EOF (which
is negative) will always fail, leaving a 255 byte at the end of the
line.  This can cause a syntax error, in turn causing the contents of
kadm5.acl to be ignored.  Fix this bug by removing the cast on EOF.

[ghudson@mit.edu: more precisely describe consequences of bug in
commit message]

ticket: 8346 (new)
target_version: 1.14-next
target_version: 1.13-next
tags: pullup