UND ADCIRC hurricane Ike links: zeta2 missing attribute

[brandonmayer-zz]

There are some datasets that recently have been returning the following error:

Error {
code = 500;
message = "New variable (zeta2) must have datatype attribute";
};

http://comt.sura.org/thredds/dodsC/data/comt_1_archive/inundation_tropical/UND_ADCIRC/Hurricane_Ike_2D_preliminary_run_9_with_waves_and_levees_and_river_flow.html

http://comt.sura.org/thredds/dodsC/data/comt_1_archive/inundation_tropical/UND_ADCIRC/Hurricane_Ike_2D_preliminary_run_8_with_waves_and_levees.html

http://comt.sura.org/thredds/dodsC/data/comt_1_archive/inundation_tropical/UND_ADCIRC/Hurricane_Ike_2D_preliminary_run_7_with_waves_without_advection_implicit_1s.html

http://comt.sura.org/thredds/dodsC/data/comt_1_archive/inundation_tropical/UND_ADCIRC/Hurricane_Ike_2D_preliminary_run_6_without_waves_and_advection_implicit_1s.html

@rsignell-usgs, @brianmckenna please review.