javareconf was leaving .old files around

git-svn-id: https://svn.r-project.org/R/trunk@63869 00db46b3-68df-0310-9c12-caf00c1e9a41
correct

git-svn-id: https://svn.r-project.org/R/trunk@63871 00db46b3-68df-0310-9c12-caf00c1e9a41
improve cleaning

git-svn-id: https://svn.r-project.org/R/trunk@63873 00db46b3-68df-0310-9c12-caf00c1e9a41
check VignetteBuilder field

git-svn-id: https://svn.r-project.org/R/trunk@63875 00db46b3-68df-0310-9c12-caf00c1e9a41