SBS/MFRSR/M1 - Channel 940 drop out

Channel 940 data dropped out.  The MFRSR head was replaced on 20110125.  The 940nm data 
did not immediately come back on-line, so likely was not a head issue.  940 did come back 
on 20110126 @ 1800 UTC.

• direct_horizontal_narrowband_filter6
• diffuse_hemisp_narrowband_filter6
• hemisp_narrowband_filter6_raw
• offset_filter6
• hemisp_narrowband_filter6
• diffuse_hemisp_narrowband_filter6_raw
• alltime_hemisp_narrowband_filter6

• direct_diffuse_ratio_filter6
• direct_horizontal_narrowband_filter6
• hemisp_narrowband_filter6
• offset_filter6
• alltime_hemisp_narrowband_filter6
• direct_normal_narrowband_filter6
• diffuse_hemisp_narrowband_filter6