Allow /proc/*/attr/current in dovecot imap and lmtp

This is needed when using the "apparmor" plugin which means dovecot
switches to user-specific hats.

Seen on openSUSE Tumbleweed.

(backported from commit 6a388859f8)
Signed-off-by: John Johansen <john.johansen@canonical.com>

profiles/apparmor.d/usr.lib.dovecot.imap

@@ -33,7 +33,7 @@
   /etc/dovecot/conf.d/** r,
 
   owner /tmp/dovecot.imap.* rw,
-
+  @{PROC}/@{pid}/attr/current rw,
   /usr/bin/doveconf rix,
   /usr/lib/dovecot/imap mrix,
   /usr/share/dovecot/** r,

profiles/apparmor.d/usr.lib.dovecot.lmtp

@@ -28,7 +28,7 @@
   @{DOVECOT_MAILSTORE}/** rwkl,
 
   @{HOME}/.dovecot.svbin r,
-
+  @{PROC}/@{pid}/attr/current rw,
   /proc/*/mounts r,
   /tmp/dovecot.lmtp.* rw,
   /usr/lib/dovecot/lmtp mr,