Safeway Inc. (NYSE:SWY) has created an anti-takeover provision, also called a poison pill, that will trigger if any investor accumulates more than 10 percent of the company’s stock, reports Tess Stynes for The Wall Street Journal. The specific reasons for taking what is normally a drastic measure are still unclear. Safeway’s mystery investor Safeway Inc. (NYSE:SWY) announced that it knows about an investor quietly buying up shares, though it did not identify the mystery investor, and said that the poison pill would guarantee the board’s freedom to pursue long-term interests without interference from an activist shareholder. Safeway is planning to sell off…