Failed to check Unique name when Realname Integration is enabled

When the Privatemsg Realname Integration module is enabled, I found some potential bugs which may come out. To reproduce the bug, please prepare the username and realname like the following

• admin : Super User
• user1 : Test User
• user2 : Test User
• user3 : User Three
• user's : User User

And also roles like the following.

• administrator
• anonymous user
• authenticated user
• user3

And then send the message directly to user by clicking the link in user's page. Try to send the message directly to the following users:
User Three
expected: User Three
actual: User Three [user: user3]
This is because the username is eventually the same as one of role name (user3).

Test User
expected: Test User [user: user1] or Test User [user: user2]
actual: Test User
Because both of them has the different username (user1 and user2).

The realname is not used to check for unique. It is just the username that is used to check for unique. So, to fix this bug I have attached the new patch.

When the Privatemsg Role module is also enabled and you type "user", the autocomplete will display the result incorrectly.
expected: user3 [role]
actual: user3

For now, I still unable to fix this bug.