MergeOp: Debug log in openBranch and validateChangeList

Change-Id: I84f61dd73eb64b01833849588ad81822c59c1efe

gerrit-server/src/main/java/com/google/gerrit/server/git/MergeOp.java

diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeOp.java b/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeOp.java
index 46619f6..66777cb 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeOp.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/git/MergeOp.java
@@ -462,6 +462,8 @@
           }
         }
       }
+      logDebug("Opened branch {}: {}, (parsed to {})",
+          destBranch.get(), oldRef, branchTip);
       return branchUpdate;
     } catch (IOException e) {
       throw new MergeException("Cannot open branch", e);
@@ -637,6 +639,7 @@
       toMerge.put(submitType, commit);
       toSubmit.put(submitType, chg);
     }
+    logDebug("Submitting on this run: {}", toSubmit);
     return toSubmit;
   }