SONAR-17833 Migration #6703 fails when coming from SonarQube 5.6 on MS SQL Server

server/sonar-db-migration/src/main/java/org/sonar/server/platform/db/migration/version/v98/DropProjectMeasureVariationColumn.java

 
 import org.sonar.db.Database;
 import org.sonar.server.platform.db.migration.step.DropColumnChange;
+import org.sonar.server.platform.db.migration.step.DropColumnWithConstraint;
 
-public class DropProjectMeasureVariationColumn extends DropColumnChange {
-
+public class DropProjectMeasureVariationColumn  extends DropColumnWithConstraint {
   public static final String TABLE_NAME = "project_measures";
   public static final String COLUMN_NAME = "variation_value_1";