[B] Modified the wording of the second IllegalArgumentException in Player.setScoreboard. Fixes BUKKIT-5149

##### The Issue:

The description of the second IllegalArgumentException in Player.setScoreboard (http://jd.bukkit.org/dev/apidocs/org/bukkit/entity/Player.html#setScoreboard(org.bukkit.scoreboard.Scoreboard)) is ambiguous as it could be interpreted as excluding the main (vanilla) scoreboard, as this might not considered to have been "created" by the scoreboard manager.

##### Justification for this PR:

This rewording avoid the confusion of the Main (vanilla) scoreboard not being considered to have been "created" by the scoreboard manager.

##### PR Breakdown:

Changed wording of the javadocs for the second IllegalArgumentException of Player.setScoreboard method from:

IllegalArgumentException - if scoreboard was not created by the scoreboard manager

To:

IllegalArgumentException - if scoreboard was not obtained from the scoreboard manager

##### Testing Results and Materials:

N/A. Minor wording change to javadocs only.

##### Relevant PR(s):

N/A

##### JIRA Ticket:

BUKKIT-5149 - https://bukkit.atlassian.net/browse/BUKKIT-5149