improve documentation about the "ignore-send-failures" attribute for Routers [INT-2055]

[spring-operator]

Manuel Jordan opened INT-2055 and commented

Exists a problematic confusion about the real explanation or context available with the description shown with STS for the attribute ignore-send-failures when is used with Routers

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Reference URL: http://forum.springsource.org/showthread.php?113441-how-test-or-work-with-ignore-send-failures-with-Routers

[spring-operator]

Gunnar Hillert commented

Issued pull request: #159