SolarWinds Inc., a maker of software for managing computer networks, agreed to be bought by private-equity firms Silver Lake Partners and Thoma Bravo in a deal valued at $4.5 billion. The firms said Wednesday they will pay SolarWinds stockholders $60.10 a share, or about 44 percent more than the company’s closing price on Oct. 8, before news emerged that it was in talks to be taken private. The shares jumped...