This indicates that the master in unhappy with the action of his servant. This is commonly understood as meaning that the master spilled the wine onto the face of his servant. However the example does precious little in adding on to the basic understanding. Rain sent by Hashem on Sukos stops us from fulfilling the mitzvoh and shows that Hashem is unhappy with us. In the days of the Talmud the wine was so strong and concentrated that without dilution it was not drinkable.
Wine is symbolic for strict judgement, midas hadin.
Water is symbolic for mercy, midas horachamim. The servant came with a container of water on Sukos to dilute the midas hadin of the previous days from Rosh Hashonoh through Yom Kippur. However, the master took the jug of water and spilled it onto the face of the servant, indicating that he was not willing to accept the water, the diluting of the strict judgement with mercy, symbolized by water. They did not return until Hashem forgave them and they had begun to build the Mishkon. The announcement for the collection took place on the day after Yom Kippur and the collection lasted through the fourteenth of Tishrei.