Getting magnitudes is incomplete

[hschovanec-usgs]

Describe the bug
Some events have more origin products than phase-data products. This means that the if/else statement may artificially limit the number of magnitudes:

libcomcat/libcomcat/classes.py

Lines 677 to 680 in d24ff03

	if self.hasProduct("phase-data"):
	product = "phase-data"
	else:
	product = "origin"

To Reproduce
See Tohoku as an example: https://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&eventid=official20110311054624120_30

There are 2 quakemls for phase-data, but 5 quakemls for origin