export.sh: Instead of doing "svn log" for every revision between $START_REV and $END_REV, lookup the revisions which actually contain changes to this branch and do "svn log" and "svn diff" only for them.
export.sh:
Instead of doing "svn log" for every revision between $START_REV and $END_REV,
lookup the revisions which actually contain changes to this branch and do
"svn log" and "svn diff" only for them.

This makes the script many times faster.

I have checked that both old and new variant create identical snapshots.


davidl-zend/zenddbi,natsys/mariadb_10.2,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,flynn1973/mariadb-aix,davidl-zend/zenddbi,ollie314/server,natsys/mariadb_10.2,natsys/mariadb_10.2,ollie314/server,natsys/mariadb_10.2,natsys/mariadb_10.2,flynn1973/mariadb-aix,ollie314/server,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,davidl-zend/zenddbi,slanterns/server,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,flynn1973/mariadb-aix,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,davidl-zend/zenddbi,natsys/mariadb_10.2,natsys/mariadb_10.2,ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,ollie314/server,ollie314/server,davidl-zend/zenddbi,flynn1973/mariadb-aix,natsys/mariadb_10.2,ollie314/server,natsys/mariadb_10.2,ollie314/server,flynn1973/mariadb-aix,ollie314/server