If VarBC is activated, EDA scenario is failing at the 2nd cycle of DA task

[byoung-joo]

Describe the bug
VarBC requires the prior information of coefficient and its covariance. At the first cycle, the specified static files are used as a prior information. Later, the previous analyzed VarBC coefficient and its covariance files are used as a prior information at current DA cycle.

For EDA scenario, the path for prior information is not populated properly and this leads to a failure of DA task at the 2nd cycle.

To Reproduce
This can be reproduced by running test/testinput/eda_OIE120km_WarmStart.yaml with adding biasCorrection: True under variational key.
The example of error message from variational runs at the 2nd cycle is as below:

Exception:      Reason: H5Fopen failed
        compat: HDF5_Version_Range: [V110, Latest (1.14.3)]
        filename:       /glade/derecho/scratch/bjung/pandac/bjung_eda_OIE120km_WarmStart_TEST_PR409_VarBC/CyclingDA/2018041500/dbOut/satbias_cov_amsua_aqua.h5
        mode:   ioda::Engines::BackendOpenModes::Read_Only
        source_column:  0
        source_filename:        /glade/work/jwittig/repos1/mpas-bundle-cron-src/mpas-bundle/ioda/src/engines/ioda/src/ioda/Engines/HH/HH.cpp
        source_function:        ioda::Group ioda::Engines::HH::openFile(const std::string&, ioda::Engines::BackendOpenModes, HDF5_Version_Range)
        source_line:    185
        stacktrace:
 0# util::stacktrace_current[abi:cxx11]() in /glade/derecho/scratch/jwittig/repos-s/mpas-bundle-cron/build-gnu-1p_02_07_26/bin/../lib64/liboops.so
 1# ioda::Exception::add_call_stack() in /glade/derecho/scratch/jwittig/repos-s/mpas-bundle-cron/build-gnu-1p_02_07_26/bin/../lib64/libioda_engines.so
 2# ioda::Exception::Exception(char const*, ioda::detail::compat::source_location::source_location const&, ioda::Options const&) in /glade/derecho/scratch/jwittig/repos-s/mpas-bundle-cron/build-gnu-1p_02_07_26/bin/../lib64/libioda_engines.so
 3# 0x0000148B55BCC283 in /glade/derecho/scratch/jwittig/repos-s/mpas-bundle-cron/build-gnu-1p_02_07_26/bin/../lib64/libioda_engines.so
 4# ioda::Engines::constructBackend(ioda::Engines::BackendNames, ioda::Engines::BackendCreationParameters&) in /glade/derecho/scratch/jwittig/repos-s/mpas-bundle-cron/build-gnu-1p_02_07_26/bin/../lib64/libioda_engines.so
 5# ufo::ObsBiasCovariance::read(eckit::Configuration const&) in /glade/derecho/scratch/jwittig/repos-s/mpas-bundle-cron/build-gnu-1p_02_07_26/bin/../lib64/libufo.so
 6# ufo::ObsBiasCovariance::ObsBiasCovariance(ioda::ObsSpace&, eckit::Configuration const&) in /glade/derecho/scratch/jwittig/repos-s/mpas-bundle-cron/build-gnu-1p_02_07_26/bin/../lib64/libufo.so
 7# 0x00000000005B60B1 in ./mpasjedi_variational.x
 8# 0x00000000005D589C in ./mpasjedi_variational.x
 9# 0x00000000005D5A58 in ./mpasjedi_variational.x
10# 0x0000000000665C54 in ./mpasjedi_variational.x
11# 0x0000000000675F95 in ./mpasjedi_variational.x
12# 0x0000000000676495 in ./mpasjedi_variational.x
13# 0x00000000005769AE in ./mpasjedi_variational.x
14# 0x0000000000676576 in ./mpasjedi_variational.x
15# oops::Run::execute(oops::Application const&, eckit::mpi::Comm const&) in /glade/derecho/scratch/jwittig/repos-s/mpas-bundle-cron/build-gnu-1p_02_07_26/bin/../lib64/liboops.so
16# 0x000000000047125B in ./mpasjedi_variational.x
17# 0x0000148B4F556E6C in /lib64/libc.so.6
18# __libc_start_main in /lib64/libc.so.6
19# 0x00000000004712A1 in ./mpasjedi_variational.x

Expected behavior
EDA can be run with VarBC. But also wondering if it is desirable.

potential fix
We need to consider multiple members (if exist) in https://github.com/NCAR/MPAS-Workflow/blob/develop/bin/PrepJEDI.csh#L278 https://github.com/NCAR/MPAS-Workflow/blob/develop/bin/PrepJEDI.csh#L347-L348 , similar to https://github.com/NCAR/MPAS-Workflow/blob/develop/bin/PrepJEDI.csh#L596-L601 .