#75 Schema setField API accept empty field name

[Pascal MERCIER]

Exemple: http://localhost:8080/oss/schema?use=indexname&cmd=setfield&field.name=&field.analyzer=TextAnalyzer&field.stored=yes&field.indexed=yes&field.termVector=positions_offsets

We can create a field with an empty name using the API but this isn't possible using the interface.

Expected: The api must return a KO with "Field name cannot be empty" (like the interface say)