Daniel Slocomb's mugshot from the Erath County Jail. By SARA VANDEN BERGE   An Erath County grand jury on Thursday indicted a Stephenville man accused of repeatedly sexually assaulting a teenager.   Fifty-six-year-old Daniel Slocomb was indicted on four counts of sexual assault of a child (enhanced), sexual performance by a child (enhanced) and two counts of indecency with a child (enhanced).     All charges are second degree felonies.   According to the official complaint ob