Workflows: fix typo in Task.dependencies name

Task.dependencies had been misspelled as dependenices in the attribute
definition, but spelled correctly in constraints definition.

This resulted in Task object have two attributes, dependenices and
dependencies.

````
import aaf.fr.workflow.*

  Task.getAll().each {
    println it
    println "    dependencies = " + it.dependencies
    println "    dependenices = " + it.dependenices
  }
````

returns

````
task:[id:1, name:Send confirmation message]
dependencies = []
dependenices = []
task:[id:2, name:Check for valid approvers]
dependencies = []
dependenices = []
task:[id:3, name:Request organization approval]
dependencies = []
dependenices = []
````

Luckily, none of the to versions of the attribute is used and both are
empty.  There is also no database mapping - so no database changes
needed.

Simple fix by changing the attribute name to the correct form.  All
tests passed.
Merge pull request #173 from University-of-Auckland/develop-fix-workflow

Workflows: fix typo in Task.dependencies name