capture: reduce possible failures

Author: xoviat

_pytest/capture.py

@@ -414,6 +414,8 @@ def resume(self):
         try:
             os.dup2(self.tmpfile_fd, self.targetfd)
         except OSError:
+            self.tmpfile = open(os.devnull, "r")
+            self.tmpfile_fd = self.tmpfile.fileno()
             self.targetfd = open(os.devnull, "r").fileno()
 
     def writeorg(self, data):