Fixed: Solr requires application/x-www-form-urlencoded (OFBIZ-12600)

Solr plugin fires exception on create/update of a product.

1.) enable eca in solrconfig.properties: solr.eca.enabled=true
2.)  enable all eca in eecas.xml
3.) start ofbiz
4.) update or create a product (go to product and save it)
the error is fired.

Thanks: Ingo Wolfmayr for report
diff --git a/solr/src/main/java/org/apache/ofbiz/solr/SolrProductSearch.java b/solr/src/main/java/org/apache/ofbiz/solr/SolrProductSearch.java
index e1d1a45..be5c890 100644
--- a/solr/src/main/java/org/apache/ofbiz/solr/SolrProductSearch.java
+++ b/solr/src/main/java/org/apache/ofbiz/solr/SolrProductSearch.java
@@ -76,6 +76,7 @@
         String solrIndexName = (String) context.get("indexName");
 
         if (SolrUtil.isSolrEcaEnabled()) {
+            System.setProperty("SolrDispatchFilter", "runsAfterControlFilter");
             // Debug.logVerbose("Solr: addToSolr: Running indexing for productId '" + productId + "'", MODULE);
             try {
                 GenericValue product = EntityQuery.use(delegator).from("Product").where("productId", productId).queryOne();
@@ -98,6 +99,7 @@
                 Debug.logError(gse, gse.getMessage(), MODULE);
                 result = ServiceUtil.returnError(gse.toString());
             }
+            System.clearProperty("SolrDispatchFilter");
         } else {
             final String statusMsg = "Solr ECA indexing disabled; skipping indexing for productId '" + productId + "'";
             if (Debug.verboseOn()) {