Somewhat hacky fix to get commit hash qualified DBs working

go/libraries/doltcore/sqle/dsess/session.go

@@ -1036,6 +1036,23 @@ func (sess *Session) AddDB(ctx *sql.Context, dbState InitialDbState) error {
 		if err != nil {
 			return err
 		}
+	} else {
+		headRoot, err := dbState.HeadCommit.GetRootValue()
+		if err != nil {
+			return err
+		}
+
+		hash, err := headRoot.HashOf()
+		if err != nil {
+			return err
+		}
+
+		err = sess.Session.SetSessionVariable(ctx, WorkingKey(db.Name()), hash.String())
+		if err != nil {
+			return err
+		}
+
+		sessionState.headRoot = headRoot
 	}
 
 	// This has to happen after SetRoot above, since it does a stale check before its work

integration-tests/bats/sql.bats

@@ -606,7 +606,7 @@ SQL
     # get the second to last commit hash
     hash=`dolt log | grep commit | cut -d" " -f2 | tail -n+2 | head -n1`
 
-    dolt sql -q "select * from \`dolt_repo_$$/$hash\`.a1 order by x;" -r csv
+    run dolt sql -q "select * from \`dolt_repo_$$/$hash\`.a1 order by x;" -r csv
     [ "$status" -eq 0 ]
     [ "${#lines[@]}" -eq 4 ]    
 }