Fix validation of hostPath

When adding a volume, this comes in mountOptions. The hostPath in the
database is the computed host path.

migrations/schema.sql

@@ -280,7 +280,7 @@ CREATE TABLE IF NOT EXISTS appPasswords(
 CREATE TABLE IF NOT EXISTS volumes(
     id VARCHAR(128) NOT NULL UNIQUE,
     name VARCHAR(256) NOT NULL UNIQUE,
-    hostPath VARCHAR(1024) NOT NULL UNIQUE,
+    hostPath VARCHAR(1024) NOT NULL UNIQUE, // computed hostPath
     creationTime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
     mountType VARCHAR(16) DEFAULT "noop",
     mountOptionsJson TEXT,