Use rsync instead of scp for file transfers to save time on cache download from VM

libexec/copy-from-target

@@ -3,7 +3,7 @@
 . gconfig
 
 TUSER=${DISTRO:-ubuntu}
-QUIET_FLAG=
+QUIET_FLAG="-vP"
 
 usage() {
   echo "Usage: ${0##*/} [OPTION]... <command>"
@@ -47,7 +47,7 @@ if [ $# = 0 ] ; then
 fi
 
 if [ -z "$USE_LXC" ]; then
-    scp $QUIET_FLAG -oConnectTimeout=30 -oNoHostAuthenticationForLocalhost=yes -i ${GITIAN_BASE:-.}/var/id_rsa -P $VM_SSH_PORT -r $TUSER@localhost:$1 $2
+    rsync --checksum -a $QUIET_FLAG -e "ssh -oConnectTimeout=30 -oNoHostAuthenticationForLocalhost=yes -i ${GITIAN_BASE:-.}/var/id_rsa -p $VM_SSH_PORT" "$TUSER@localhost:$1" "$2"
 else
     config-lxc
     sudo $LXC_EXECUTE -n gitian -f var/lxc.config -- sudo -i -u $TUSER tar -C `dirname "$1"` -cf - `basename "$1"` | tar -C "$2" -xf -

libexec/copy-to-target

@@ -3,7 +3,7 @@
 . gconfig
 
 TUSER=${DISTRO:-ubuntu}
-QUIET_FLAG=
+QUIET_FLAG="-vP"
 
 usage() {
   echo "Usage: ${0##*/} [OPTION]... <command>"
@@ -47,7 +47,7 @@ if [ $# = 0 ] ; then
 fi
 
 if [ -z "$USE_LXC" ]; then
-    scp $QUIET_FLAG -r -oConnectTimeout=30 -oNoHostAuthenticationForLocalhost=yes -i ${GITIAN_BASE:-.}/var/id_rsa -P $VM_SSH_PORT $1 $TUSER@localhost:$2
+    rsync --checksum -a $QUIET_FLAG -e "ssh -oConnectTimeout=30 -oNoHostAuthenticationForLocalhost=yes -i ${GITIAN_BASE:-.}/var/id_rsa -p $VM_SSH_PORT" "$1" "$TUSER@localhost:$2"
 else
     config-lxc
     tar -C `dirname "$1"` -cf - `basename "$1"` | sudo $LXC_EXECUTE -n gitian -f var/lxc.config -- sudo -i -u $TUSER tar -C "$2" -xf -