OO-1000: remove a constraint which kill support of MySQL 5.1

src/main/java/org/olat/upgrade/_spring/databaseUpgradeContext.xml

@@ -64,6 +64,10 @@
 					<constructor-arg index="0" value="OLAT_9.4.0" />
 					<property name="alterDbStatements" value="alter_9_3_0_to_9_4_0.sql" />
 				</bean>
+				<bean id="database_upgrade_10_0_0" class="org.olat.upgrade.DatabaseUpgrade">
+					<constructor-arg index="0" value="OLAT_10.0.0" />
+					<property name="alterDbStatements" value="alter_9_4_0_to_10_0_0.sql" />
+				</bean>
 			</list>
 		</property>
 	</bean>

src/main/resources/database/mysql/alter_9_4_0_to_10_0_0.sql

@@ -35,7 +35,7 @@ insert into o_repositoryentry_stats (id, creationdate, lastmodified, r_rating, r
 update o_repositoryentry set fk_stats=repositoryentry_id where fk_stats is null;
 
 alter table o_repositoryentry modify fk_stats bigint not null;
-alter table o_repositoryentry add constraint repoentry_stats_ctx foreign key (fk_stats) references o_repositoryentry_stats (id);
+-- alter table o_repositoryentry add constraint repoentry_stats_ctx foreign key (fk_stats) references o_repositoryentry_stats (id);
 
 -- base group
 create table o_bs_group (

src/main/resources/database/mysql/setupDatabase.sql

@@ -2058,7 +2058,7 @@ create index idx_re_lifecycle_extref_idx on o_repositoryentry (external_ref);
 alter table o_repositoryentry add constraint idx_re_lifecycle_fk foreign key (fk_lifecycle) references o_repositoryentry_cycle(id);
 create index idx_re_lifecycle_soft_idx on o_repositoryentry_cycle (r_softkey);
 
-alter table o_repositoryentry add constraint repoentry_stats_ctx foreign key (fk_stats) references o_repositoryentry_stats (id);
+-- alter table o_repositoryentry add constraint repoentry_stats_ctx foreign key (fk_stats) references o_repositoryentry_stats (id);
 
 -- access control
 create index ac_offer_to_resource_idx on o_ac_offer (fk_resource_id);