Remove requirement of "Signed-off-by" in the commit message.

The regulation has been changed to rely on commit mete-information.

Author: basilevs

CONTRIBUTING.md

@@ -18,18 +18,11 @@
 ## Eclipse Contributor Agreement
 
 Before your contribution can be accepted by the project team contributors must
-electronically sign the Eclipse Contributor Agreement (ECA).
-
+electronically sign the Eclipse Contributor Agreement (ECA). For more information, please see the Eclipse Committer Handbook:
+* https://www.eclipse.org/projects/handbook/#resources-commit
 * http://www.eclipse.org/legal/ECA.php
 
-Commits that are provided by non-committers must have a Signed-off-by field in
-the footer indicating that the author is aware of the terms by which the
-contribution has been provided to the project. The non-committer must
-additionally have an Eclipse Foundation account and must have a signed Eclipse
-Contributor Agreement (ECA) on file.
 
-For more information, please see the Eclipse Committer Handbook:
-https://www.eclipse.org/projects/handbook/#resources-commit
 
 ## Contact