Use erase instead of rewrite to remove old addr entries

Use erase instead of rewrite to remove old addr entries

* Invalidate the previous chaintip when rolling back the chain.

This prevents the chain from automatically trying to reconnect
when or if the next block arrives.

* Allow override in order rollbackchain more than 100 blocks

* Must mark BLOCK_FAILED_VALID for all chains when rolling back.

If you rollback a chain beyond a fork point you must make sure
to mark all the blocks in all chains as failed otherwise if you
try to reconnect the same chain you just unwound then you'll get
an assertion in CheckBlock() because pindexFirstInvalid will be
NULL and then you'll assert on BLOCK_FAILED_MASK.

* switch to C++11 range based loops in unlimited.cpp

* Add tests to blockchain.py for rolling back beyond the fork point.

When we rollback we may roll back beyond one or more forks and
we must be able to reconsider which ever fork we want to follow.

11e9406 Raise min required symbols (Peter Bushnell)

Pull request description:

  This is to allow Gitian building for without generating symbol errors for bitcoin-wallet and test/test_omnicore. Omnicore binaries omnicored, omnicore-cli and omnicore-qt do not generate symbol errors.

Tree-SHA512: d02545a0cc7cc9a5f4695812a156ae585ea92d72f30ac65d3e531d1212cc2e8af738132472f47b147fc0a66e8c62b2d5f524f1c0a2f7879113204dcdbe083826