Fix TaskEvent.processType type at some databases for hibernate validation

After jbpm#1680 hibernate validation is failing for some databases due to an incorrect type definition for TaskEvent.processType:

Caused by: org.hibernate.tool.schema.spi.SchemaManagementException: Schema-validation: wrong column type encountered in column [processType] in table [dbo.TaskEvent]; found smallint (Types#SMALLINT), but expecting int (Types#INTEGER)