You can read the story
here. Not sure why the OP blames Bush for this since he was not given all the information at the time.
"As the execution drew near, Jones was pressing the governor's office for permission to do a DNA test on the hair. But the briefing papers Bush was given by his staff didn't include the request for the testing, and Bush denied a reprieve, according to state documents obtained by the Innocence Project"
Also looks like given that information he would have probably given a stay
"Bush had previously shown a willingness to test DNA evidence that could prove guilt or innocence in death penalty cases. Earlier in 2000, he had granted a reprieve to a death row inmate so that Scheck and other attorneys could have evidence tested. The test confirmed the man's guilt and he was executed"