OSGI cache should be excluded from backup

Customers reported issues where they struggled to restore Fisheye backups. Although backups seems correct, when they run restore command it fails with error like:

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGBUS (0x7) at pc=0x00007fd4cffb7a82, pid=25426, tid=140552036337408
#
# JRE version: 7.0_07-b10
# Java VM: Java HotSpot(TM) 64-Bit Server VM (23.3-b01 mixed mode linux-amd64 compressed oops)
# Problematic frame:
# C  [libzip.so+0x4a82]  newEntry+0x62
#

Even when disableMemoryMapping property is set to avoid SIGBUS error

FISHEYE_OPTS="-Dsun.zip.disableMemoryMapping=true " restore -f ...

(further details: http://mail.openjdk.java.net/pipermail/core-libs-dev/2010-February/003636.html http://cr.openjdk.java.net/~sherman/6929479/webrev/ )

the restore still fails.

It seems the issue is caused by having osgi cache being included in the backup file. There is no point of including this cache, as felix would easily recreate this cache on startup.