Purchase mortgages are getting to be a tougher sell as many potential homebuyers say high prices make it a lousy time to buy a house, and sellers are getting less enthusiastic as well. A Fannie Mae survey found that the share of people surveyed who said it was a bad time to buy reached a high of 57 percent in July, while the share who said it was a good time to buy hit a low, 34 percent. The government-sponsored enterprise has been conducting the survey since 2011. “It’s...