Correct typo (bug 5-typo-in-model-project_milestonerb)
Correct typo (bug 5-typo-in-model-project_milestonerb)

- Thanks to gylf for reporting this issue

UWC4C/Railscollab,rajeshrsmail/railscollab,silliemunkie/cpsprojectmanagement,silliemunkie/cpsprojectmanagement,kakra/railscollab,UWC4C/Railscollab,kakra/railscollab,rajeshrsmail/railscollab