Description of problem:
pflogsumm emits many warnings (to stderr) when maillog contains IPv6 addresses.

Version-Release number of selected component (if applicable):
postfix-perl-scripts-3.0.7-1.fc23.x86_64

How reproducible:
Always.

Steps to Reproduce:
1. Given /var/log/maillog containing lines like:
Oct 13 00:33:24 doumeki postfix/smtpd[9148]: disconnect from localhost[::1] ehlo=1 mail=1 rcpt=1 data=1 commands=4
Oct 13 01:29:12 doumeki postfix/smtpd[14127]: disconnect from se01.ovh6.rpmfusion.net[2001:41d0:2:ad32::1] ehlo=1 mail=1 rcpt=1 data=1 quit=1 commands=5
Oct 13 02:21:47 doumeki postfix/smtpd[18076]: disconnect from mail-yb0-x22e.google.com[2607:f8b0:4002:c09::22e] ehlo=2 starttls=1 mail=1 rcpt=1 data=1 quit=1 commands=7
2. /usr/sbin/pflogsumm -q -d yesterday -h 10 --ignore_case --smtpd_warning_detail=0 --mailq --problems_first --smtpd_stats --verp_mung=2 --zero_fill /var/log/maillog

Actual results:
Use of uninitialized value $domain in string eq at /usr/sbin/pflogsumm line 1539, <> line 62693.
Use of uninitialized value $domain in substitution (s///) at /usr/sbin/pflogsumm line 1545, <> line 62693.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 768, <> line 62693.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 769, <> line 62693.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 770, <> line 62693.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 772, <> line 62693.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 774, <> line 62693.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 773, <> line 62693.
Use of uninitialized value $domain in string eq at /usr/sbin/pflogsumm line 1539, <> line 63259.
Use of uninitialized value $domain in substitution (s///) at /usr/sbin/pflogsumm line 1545, <> line 63259.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 768, <> line 63259.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 772, <> line 63259.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 774, <> line 63259.
Use of uninitialized value $domain in string eq at /usr/sbin/pflogsumm line 1539, <> line 64377.
Use of uninitialized value $domain in substitution (s///) at /usr/sbin/pflogsumm line 1545, <> line 64377.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 768, <> line 64377.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 772, <> line 64377.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 774, <> line 64377.
Use of uninitialized value $hostID in hash element at /usr/sbin/pflogsumm line 773, <> line 64377.

(lines 62693, 63259 and 64377 are posted above)

Expected results:
No perl warnings in the output.

Additional info:
It looks like parsing in the gimme_domain function doesn't support IPv6 addresses. Here's a patch that fixes it for me:

--- /usr/sbin/pflogsumm	2016-10-03 13:39:01.000000000 +0200
+++ /root/bin/pflogsumm	2016-10-14 12:22:34.851472588 +0200
@@ -1529,7 +1529,7 @@
     # split domain/ipaddr into separates
     # newer versions of Postfix have them "dom.ain[i.p.add.ress]"
     # older versions of Postfix have them "dom.ain/i.p.add.ress"
-    unless((($domain, $ipAddr) = /^([^\[]+)\[((?:\d{1,3}\.){3}\d{1,3})\]/o) == 2 ||
+    unless((($domain, $ipAddr) = /^([^\[]+)\[((?:\d{1,3}\.){3}\d{1,3}|[0-9a-f:]+)\]/o) == 2 ||
            (($domain, $ipAddr) = /^([^\/]+)\/([0-9a-f.:]+)/oi) == 2) {
 	# more exhaustive method
         ($domain, $ipAddr) = /^([^\[\(\/]+)[\[\(\/]([^\]\)]+)[\]\)]?:?\s*$/o;