You're able to search for non-analyzed field query but there will be a match only in case of field value being completely equals to search term. As mindas mentioned - phrase query should be used for that.
In case you want to search for that field, you'd need to reindex your documents with that field being analyzed.
You can try using existing Analyzers / Tokenizers (i.e. set StandardAnalyzer when creating IndexWriter, for example) or implement your own one that will split file path into tokens using file separator as delimiter.
In case you're interested, there's Solr's PathHierarchyTokenizerFactory that already splits some hierarchical path into tokens before storing then to index and that makes file path search much easier.