Bug fix: Only try to find decoder for zip, 7z once

[Quanah Gibson-Mount via amavis-users]

Currently at startup, Amavis tries to find a decoder for 7z and zip 
extensions twice:

[zimbra at edge01 ~]$ grep "Found decoder for" /var/log/zimbra.log | grep 
16:53:45

May  1 16:53:45 edge01 amavis[3396]: Found decoder for    .zip  at 
/usr/bin/7za
May  1 16:53:45 edge01 amavis[3396]: Found decoder for    .kmz  at 
/usr/bin/7za
May  1 16:53:45 edge01 amavis[3396]: Found decoder for    .7z   at 
/usr/bin/7za
May  1 16:53:45 edge01 amavis[3396]: Found decoder for    .7z   at 
/usr/bin/7za (backup, not used)
May  1 16:53:45 edge01 amavis[3396]: Found decoder for    .zip  at 
/usr/bin/7za (backup, not used)

This can be fixed via the following patch:

[root at zre-ldap003 sbin]# diff -du amavisd.orig amavisd
--- amavisd.orig        2014-05-01 17:47:06.446113729 -0700
+++ amavisd     2014-05-01 17:47:52.835113700 -0700
@@ -1654,7 +1654,7 @@
     [['zip','kmz'], \&Amavis::Unpackers::do_7zip,  ['7za', '7z'] ],
     [['zip','kmz'], \&Amavis::Unpackers::do_unzip],
     ['7z',   \&Amavis::Unpackers::do_7zip,  ['7zr', '7za', '7z'] ],
-    [[qw(7z zip gz bz2 Z tar)],
+    [[qw(gz bz2 Z tar)],
              \&Amavis::Unpackers::do_7zip,  ['7za', '7z'] ],
     [[qw(xz lzma jar cpio arj rar swf lha iso cab deb rpm)],
              \&Amavis::Unpackers::do_7zip,  '7z' ],


--Quanah

-- 
Quanah Gibson-Mount
Server Architect
Zimbra, Inc
--------------------
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