Add test case for compression level
Add test case for compression level

A save run with 0 and 9 are made and the size of the resuling repos is
compared.

Signed-off-by: Zoran Zaric <d7dacae2c968388960bf8970080a980ed5c5dcb7@zoranzaric.de>

ToxicFrog/bup,mhoeher/bup,jbaber/bup,pombredanne/bup,gevaerts/bup,mhoeher/bup,gevaerts/bup,tjanez/bup,jbaber/bup,apenwarr/bup,ToxicFrog/bup,pombredanne/bup,mhoeher/bup,ToxicFrog/bup,pombredanne/bup,tjanez/bup,pombredanne/bup,ToxicFrog/bup,jbaber/bup,tjanez/bup,gevaerts/bup,apenwarr/bup,jbaber/bup,tjanez/bup,apenwarr/bup,pombredanne/bup,jbaber/bup,pombredanne/bup,apenwarr/bup,mhoeher/bup,ToxicFrog/bup,gevaerts/bup,gevaerts/bup,tjanez/bup,jbaber/bup,mhoeher/bup,mhoeher/bup,tjanez/bup