Fixed version of importing snippet (tested with Neo4j 2.3.2)

beginning-neo4j-importing-relationships.cql

USING PERIODIC COMMIT 500
LOAD CSV WITH HEADERS FROM 'file:///home/mbusch/neo4j-playground/beginning_neo4j_example.csv' AS row
MATCH (p:Person {id: row.id})
MATCH (friend:Person {id: row.friend_id})
WHERE row.friend_id IS NOT NULL
MERGE (p)-[f:FRIENDS_WITH]->(friend);