fix condition

Hi @aho!

My worst nightmares become true. This branch fix the problem created in the previous fix for metadata.

Now, the tests pass and the following code also work:

sdate <- c('20170101')
path <- list(name = 'system4_m1',
                   path = file.path('/esarchive/exp/ecmwf',
                                    '$EXP_NAME$/$STORE_FREQ$_mean',  #month_mean',
                                    '$VAR_NAME$_f6h/$VAR_NAME$_$START_DATE$.nc'))
time_length <- 7
 data_Load <- Load(var = 'tas',
                     exp = list(path),
                     sdates = sdate,
                     storefreq = "monthly",
                     leadtimemax = time_length,
                     output = 'lonlat',
                     nmember = 1, nprocs = 1)

Please, check whatever you consider necessary and go head with the merge or provide me some feedback.

Cheers,

Núria