Check existence of Blacklight settings file
Check existence of Blacklight settings file

Merge of Blacklight solr settings failed on initialize before the
Blacklight generator runs; this made it impossible run the generator
unless some config files had been created manually. The initializer now
checks for the existence of the file before trying to merge the
Blacklight solr settings with Krikri's.

dpla/KriKri,dpla/KriKri,dpla/KriKri,dpla/KriKri