Update webdav proxy config generation

[Benzene]

To make things work on my side, I had to configure apache so that a config block for a mounted webdav folder looks like:

<Location /webdav/mriviere@kth.se/b2drop/ >
  RequestHeader set Authorization "Basic XXXXXXXXXXXXXXXXXX"
  RequestHeader set Host "b2drop.eudat.eu"
  ProxyPreserveHost On
  ProxyPass "https://b2drop.eudat.eu/remote.php/webdav/"
  ProxyPassReverse "https://b2drop.eudat.eu/remote.php/webdav/"
</Location>

I'm not sure why it didn't work directly with the config you had. But anyway, the things I had to add (compared to the current version of mountb2drop.sh) were:

• Add a trailing '/' at the end of the ProxyPass and ProxyPassReserve directives. I think this isn't even something to change in mountb2drop, but maybe more in the MetadataService that calls.
• Add the "ProxyPreserveHost" and "RequestHeader" directives. Adding ProxyPreserveHost is easy, but I'm not sure how to generate the "b2drop.eudat.eu" part of the RequestHeader line.

My updated mountb2drop.sh looks like the following. It's wrong to hardcode b2drop.eudat.eu in there, but I'm not sure how else to do it. Maybe there is a way to extract it from [url], but I'm not very good at bash.

function addapacheproxy {
  removeapacheproxy $2
  SFILE2=/tmp/secrets2
  echo -n $3:$4 > $SFILE2
  if [ -e $SFILE2 ]; then
    AUTH="$(base64 -w 0 $SFILE2)"
    #echo $AUTH
    echo "<Location $2 >" | sudo tee -a ${HTTPD_CONF}
    echo "  RequestHeader set Authorization \"Basic $AUTH\"" | sudo tee -a ${HTTPD_CONF} > /dev/null
    echo "  RequestHeader set Host b2drop.eudat.eu" | sudo tee -a ${HTTPD_CONF}
    echo "  ProxyPreserveHost On" | sudo tee -a ${HTTPD_CONF}
    echo "  ProxyPass \"$1\"" | sudo tee -a ${HTTPD_CONF}
    echo "  ProxyPassReverse \"$1\"" | sudo tee -a ${HTTPD_CONF}
    echo "</Location>" | sudo tee -a ${HTTPD_CONF}
    sudo service ${HTTPD_SERVICE} reload
  fi  
  rm $SFILE2
}

function removeapacheproxy {
 echo removing apache proxy
 L1=`grep -n -m 1 "\<Location $1" ${HTTPD_CONF} | cut -f1 -d:`
 echo from row $L1
 if [ $L1 > 0 ]; then #???
   let L2=$L1+6
   echo to row $L2
   sudo sed -i "$L1,$L2 d" ${HTTPD_CONF}
 fi
}