[log] Supply correct commit object to getCommitData in DetailsPanel

Introduce AbstractVcsLogTableModel#getCommit which returns a Node for
the graph table, and Hash - for the non-graph one.

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/frame/DetailsPanel.java

@@ -104,12 +104,13 @@ class DetailsPanel extends JPanel implements ListSelectionListener {
       int row = rows[0];
       AbstractVcsLogTableModel tableModel = (AbstractVcsLogTableModel)myGraphTable.getModel();
       Hash hash = tableModel.getHashAtRow(row);
-      if (hash == null) {
+      Object commit = tableModel.getCommit(row);
+      if (hash == null || commit == null) {
         showMessage("No commits selected");
         return;
       }
 
-      VcsFullCommitDetails commitData = myLogDataHolder.getCommitDetailsGetter().getCommitData(hash, tableModel.getAroundProvider());
+      VcsFullCommitDetails commitData = myLogDataHolder.getCommitDetailsGetter().getCommitData(commit, tableModel.getAroundProvider());
       if (commitData instanceof LoadingDetails) {
         myLoadingPanel.startLoading();
         myDataPanel.setData(null);

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/tables/AbstractVcsLogTableModel.java

@@ -100,6 +100,9 @@ public abstract class AbstractVcsLogTableModel<CommitColumnClass, CommitId> exte
   @Nullable
   public abstract Hash getHashAtRow(int row);
 
+  @Nullable
+  public abstract CommitId getCommit(int row);
+
   @Override
   public Class<?> getColumnClass(int column) {
     switch (column) {

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/tables/GraphTableModel.java

@@ -134,9 +134,14 @@ public class GraphTableModel extends AbstractVcsLogTableModel<GraphCommitCell, N
   @Nullable
   @Override
   public Hash getHashAtRow(int row) {
-    Node node = myDataPack.getGraphModel().getGraph().getCommitNodeInRow(row);
+    Node node = getCommit(row);
     return node == null ? null : myDataHolder.getHash(node.getCommitIndex());
-    
+  }
+
+  @Nullable
+  @Override
+  public Node getCommit(int row) {
+    return myDataPack.getGraphModel().getGraph().getCommitNodeInRow(row);
   }
 
   @NotNull

platform/vcs-log/impl/src/com/intellij/vcs/log/ui/tables/NoGraphTableModel.java

@@ -124,6 +124,12 @@ public class NoGraphTableModel extends AbstractVcsLogTableModel<CommitCell, Hash
     return myCommits.get(row).getHash();
   }
 
+  @Nullable
+  @Override
+  public Hash getCommit(int row) {
+    return getHashAtRow(row);
+  }
+
   @NotNull
   @Override
   public AroundProvider<Hash> getAroundProvider() {