Null Asset Check

[kameshsampath]

Check if Asset is not null, the directories are usually will be null asset e.g when reading with reading a path Node Children of /META-INF/services, which returns /META-INF/services/org there will be no asset associated with it since its a directory, hence we need to check if the asset is null before reading the stream of Asset content, as we are interested only in reading the content of SPI file.

@cescoffier, thoughts and comments. If you are ok I will merge this

[davsclaus]

[merge]

[davsclaus]

lgtm