APIClient: Fixing a problem with getString

The javax does not handle parsing JsonValue directly. So it is replaced
for the getString with a direct removal of the quotations.

The alternative is to replace the javax parser with a different one.

Signed-off-by: Amnon Heiman <amnon@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>

src/main/java/com/cloudius/urchin/api/APIClient.java

@@ -117,7 +117,8 @@ public class APIClient {
     }
 
     public String getStringValue(String string, MultivaluedMap<String, String> queryParams) {
-        return getReader(string, queryParams).toString();
+        return getRawValue(string,
+                queryParams).replaceAll("^\"|\"$", "");
     }
 
     public String getStringValue(String string) {