Fix ftest failure

  When a pom file changed in a hosted repo, it will trigger a
maven-metadata removing in the GA level and cascading removing for
affected groups. For fix problem of this, we use DownloadManager.delete
to solve readonly hosted repo deletion not allowed problem, but it does
not support clear group metadata. So this fix will allow remove the
mergable metadata through that method.

Author: ligangty

core/src/main/java/org/commonjava/indy/core/content/DefaultDownloadManager.java

@@ -970,7 +970,14 @@ public boolean delete( final ArtifactStore store, final String path, final Event
 
         if ( store.getKey().getType() == StoreType.group )
         {
-            return false;
+            // We should allow deletion of the group level mergeable metadata here, for supporting
+            // the cascading deletion from hosted member pom file deletion. See MetadataMergePomChangeListener.metaClear
+            // for details
+            final SpecialPathInfo pathInfo = specialPathManager.getSpecialPathInfo( path );
+            if ( pathInfo == null || !pathInfo.isMetadata() || !pathInfo.isMergable() )
+            {
+                return false;
+            }
         }
 
         if ( storeManager.isReadonly( store ) && !isIgnoreReadonly( eventMetadata ) )

embedder/src/it/resources/logback.xml

@@ -36,6 +36,7 @@
   <logger name="org.commonjava" level="TRACE" />
   <logger name="org.commonjava.indy.model.core.StoreKey" level="INFO" />
   <logger name="org.commonjava.indy.pkg.npm.content.NPMStoragePathCalculator" level="INFO" />
+  <logger name="org.commonjava.indy.metrics" level="INFO" />
   <!-- <logger name="org.commonjava.maven.galley.transport" level="DEBUG" /> -->
 
   <root level="INFO">

embedder/src/test/resources/logback-test.xml

@@ -46,6 +46,7 @@
   <logger name="org.commonjava.maven.galley" level="TRACE"/>
   <logger name="org.commonjava.indy.model.core.StoreKey" level="INFO" />
   <logger name="org.commonjava.indy.pkg.npm.content.NPMStoragePathCalculator" level="INFO" />
+  <logger name="org.commonjava.indy.metrics" level="INFO" />
 
   <root level="INFO">
     <appender-ref ref="STDOUT" />