Mention RedHat's patches for previous commits.

Mention RedHat's patches for previous commits.

Merge RedHat's patch shadow-4.0.18.1-findNewUidOnce.patch:
	* src/useradd.c (usr_update): Do not call find_new_uid(). The UID was
	already either specified or found by another call to find_new_uid().
	* src/useradd.c (find_new_uid): Always start with uid_min (find_new_uid()
	is never called when user_id was already specified).
	* src/useradd.c (find_new_uid): Fix the comments (find_new_uid() is not
	called when the UID is specified (uflg)).
	* src/useradd.c (main): Only call find_new_uid() if (!oflg) and (!uflg).
	If uflg is set (but not oflg), check the UID uniqueness.
	* src/useradd.c (find_new_uid): Don't check the uid and user name
	uniqueness in find_new_uid(). The user name uniqueness is already checked
	during the parameter validation. UID uniqueness is also checked (see
	above).
	* src/useradd.c (find_new_uid): Don't check uflg in find_new_uid().
	* src/useradd.c (find_new_uid): Make sure that find_new_uid() is not
	called when uflg is set (assert).

Cleanups in find_new_gid:
	* src/useradd.c (find_new_gid): Check that gflg is not set (assert).
	* src/useradd.c (find_new_gid): Do not check the group name uniqueness
	(already checked in main).
	* src/useradd.c (find_new_gid): Avoid a "continue" in the loop.
	* src/useradd.c (find_new_gid): Remove irrelevant comments.
	* src/useradd.c (find_new_gid): Fix the function definition's comment.