Selection of "Input file format" in the MetaPhlAn2 workflow element

Error message is not clear enough when "FASTA" format is selected in the "Input file format" parameter of the MetaPhlAn2 element, but a FASTQ file is passed to the input port of the element.

For example, in case of "Parallel classification for SE reads" workflow sample, the error message is:

IOError[Error 32] Broken pipe

In case of "Parallel classification for PE reads" the error message is:

"Error while running botwie2"

It would be better in these sample to set "Input file format" to "FASTQ" by default.