java: ignore suppressed exceptions

Java exceptions can form a tree - every exception can have reference to
exception that caused it and to a list of exceptions that were
suppressed during handling[1]. We cannot take the suppressed exceptions
into account without changing the uReport format, therefore this commit
makes the java parser ignore them.

[1] http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html

Fixes rhbz#1034857.

Signed-off-by: Martin Milata <mmilata@redhat.com>