add onetime fix of HFMETAR precip #85
add onetime fix of HFMETAR precip #85

Turns out that Trace values within the HFMETAR netcdf files are
represented by 0.005 inches.  So we need to correct the database for
this.
akrherz/iem,akrherz/iem,akrherz/iem,akrherz/iem,akrherz/iem