Add the getName() method in order to obtain the applied label to the Trident stream.

[alex-87]

Being able to get the applied label of a Trident stream could be useful in case of complex Trident topology design. The getter returns the String corresponding to the _name attribute of the Stream object.

[srdo]

The changes look good to me. Please raise an issue at https://issues.apache.org/jira and rename this PR and the commit message to contain the issue number.

[HeartSaVioR]

@alex-87 Sorry I'm late on party. Could you follow up @srdo guide?

[rzo1]

Fixed with https://github.com/apache/storm/commit/c158dee8c12aa6547c8037596c797da2f48c348d