Remove "rules" - email addresses

[Andreas Kuhn]

I believe there is still a crucial bug in [rules - email]

The following applies to an existing [group1].

I can recreate a case - using two accounts - where the managing
ACCOUNT1 removes [rule group1 email2] of ACCOUNT2 and ACCOUNT2 still
enjoys full rights to [group1]. The case also appears to create issues
for members to [join group1] if their [email] was previously used in
ACCOUNT1 [group1]. It should be noted that this occurs when [rule
group1] contains SEVERAL emails.

After removing [rule group1 email2] in "Edit rules" and pressing
<remove> the list [rule group1 email] shows the changes.

---->>>> After <save>[group1] - the [rule group1 email] shows NO
CHANGE. This may be at the heart of the subsequent issues mentioned
above.