Apply to h3

Fix for [HER-1225] HtmlFormCredential.java may create non-wellformed URLs
* HtmlFormCredential.java
    only insert '&' if previous query-string was non-empty

modules/src/main/java/org/archive/modules/credential/HtmlFormCredential.java

@@ -31,6 +31,7 @@ import org.apache.commons.httpclient.NameValuePair;
 import org.apache.commons.httpclient.URIException;
 import org.apache.commons.httpclient.methods.GetMethod;
 import org.apache.commons.httpclient.methods.PostMethod;
+import org.apache.commons.lang.StringUtils;
 import org.archive.modules.ProcessorURI;
 import org.archive.net.UURI;
 import org.archive.net.UURIFactory;
@@ -167,8 +168,11 @@ public class HtmlFormCredential extends Credential {
             String currentQuery = hmb.getQueryString();
             hmb.setQueryString(data);
             String newQuery = hmb.getQueryString();
-            hmb.setQueryString(((currentQuery != null)? currentQuery: "") +
-            		"&" + newQuery);
+            hmb.setQueryString(
+                ((StringUtils.isNotEmpty(currentQuery))
+                        ? currentQuery + "&"
+                        : "")
+                + newQuery);
             result = true;
         } else {
             logger.severe("Unknown method type: " + method);