SGP/EBBR - EBBR E7 Soil Moistures #2 and #4 Incorrect

Soil moisture #2 and #4 were negative, often large negative, during very
dry soil conditions, causing several other quantities to also be incorrect. 

The affected data are:

15 minute: r_sm2, r_sm4
30 minute: sm2, sm4, c_shf2, c_shf4, cs2, cs4, ces2, ces4, g2, g4,
           ave_shf, h, e

• soil_moisture_4_r
• soil_moisture_2_r

• latent_heat_flux
• soil_moisture_4
• soil_moisture_2
• surface_soil_heat_flux_4
• surface_soil_heat_flux_2
• corr_soil_heat_flow_2
• soil_heat_capacity_2
• corr_soil_heat_flow_4
• surface_soil_heat_flux_avg
• soil_heat_capacity_4
• energy_storage_change_4
• sensible_heat_flux
• energy_storage_change_2