`assess_inventory_sites` file read fails if extra line at the end of the inventory control file is present

[glemieux]

I ran into a run-time failure at the following line that was cause by there being an extra empty line at the end of the inventory control file:

fates/main/FatesInventoryInitMod.F90

Lines 585 to 586 in 1be3962

	! Parse the format identifier
	read(site_str,*) file_format

This should be improved to avoid crashing the model with more robust file handling.