oliver limberg <> in camel-git

CAMEL-14633 (#3603)

* CAMEL-14633 - added tests to verify missing attachments after safe copy without headers

The new two tests will make a safe copy of the exchange.

in both tests, the in and the out message have a attachment but in only one

of the tests will set an header on the messages before copying the exchange.

The test without headers will fail.

* CAMEL-14633 - fixed issue of missing attachments

Moved logic to copy attachments outside of if-block to check for existence

of headers

* fixed Checkstyle errors

* check for existence of attachments on in and out message before calling the copy method