remove duplicate changelog referenece after rebase

Author: RonnyPfannschmidt

CHANGELOG.rst

@@ -31,7 +31,6 @@
 .. _#607: https://github.com/pytest-dev/pytest/issues/607
 .. _#1519: https://github.com/pytest-dev/pytest/pull/1519
 .. _#1664: https://github.com/pytest-dev/pytest/pull/1664
-.. _#1618: https://github.com/pytest-dev/pytest/pull/1618
 
 
 2.10.0.dev1