Mismatch between filename time and first scanline time in file

[jmittaz]

TIme used for filename generation is not the same as the first time in the easy fcdr.

TIme used for filename is taken from piece directory list
Time in file is taken from piece_easy which is a processed version of piece through debug2easy.

Example is

piece time of first scanline = 2000-02-01T03:42:00.928000000
piece_easy time of first scanline = 2000-02-01T03:42:13.728000000

for file for NOAA-14 from print statements embedded in code. Relates to file

FIDUCEO_FCDR_L1C_HIRS2_N14_20000201034200_20000201052352_EASY_v0.8rc1_no_harm_fv2.0.0.nc

generated from latest version of the code (updated 19/02/2019). Issue for other parts of project that may use filename as indicator of time of first line. Presumably a bug - either time from piece should not be used or bug in debug2easy. Note most of the time this does not seem to be a problem (other files one day OK) - but noticed as part of batch processing of HIRS FCDR data for Level 2 generation. Not known how prevalent, but causing problems.

[jmittaz]

By moving where the filename is created into the piece_store_* routines this seems to fix the problem