[do_jdbc] Fix path handling when connecting with a URI

* Normalize the path element when building a java.net.URI:
  the path element should begin with a '/' character to ensure
  that the JDBC URL created internally, and passed to
  java.sql.DriverManager#getConnection, is correctly formatted.

[#1052 state:resolved]

Signed-off-by: Alex Coles <alex@alexcolesportfolio.com>

do_jdbc/src/main/java/data_objects/drivers/AbstractDriverDefinition.java

@@ -117,8 +117,14 @@ public URI parseConnectionURI(IRubyObject connection_uri)
             if (host != null && !"".equals(host)) {
                 // a client/server database (e.g. MySQL, PostgreSQL, MS
                 // SQLServer)
+                String normalizedPath;
+                if (path != null && path.length() > 0 && path.charAt(0) != '/') {
+                    normalizedPath = '/' + path;
+                } else {
+                    normalizedPath = path;
+                }
                 uri = new URI(this.jdbcScheme, userInfo.toString(), host, port,
-                        path, query, fragment);
+                        normalizedPath, query, fragment);
             } else {
                 // an embedded / file-based database (e.g. SQLite3, Derby
                 // (embedded mode), HSQLDB - use opaque uri