dup: Fix buggy version comparison. (Redmine#6746)

### duplicity version (ignore anything else than 0-9 and ".")

duplicity_version="`duplicity --version | @AWK@ '{print $2}' | @SED@ 's/[^.[:digit:]]//g'`"

duplicity_major="`echo $duplicity_version | @AWK@ -F '.' '{print $1}'`"

duplicity_minor="`echo $duplicity_version | @AWK@ -F '.' '{print $2}'`"

duplicity_sub="`echo $duplicity_version | @AWK@ -F '.' '{print $3}'`"

### ssh/scp/sftp options (duplicity < 0.4.3 is unsupported)

## duplicity >= 0.6.17 : paramiko backend

if [ "$duplicity_major" -ge 0 -a "$duplicity_minor" -ge 6 -a "$duplicity_sub" -ge 17 ]; then

if version_ge "$duplicity_version" '0.6.17'; then

   if [ -n "$sshoptions" ]; then

      if echo "$sshoptions" | grep -Eqs '^-o[[:space:]]*IdentityFile=[^ ]+$' ; then

         spaceless_sshoptions="$(echo -n "$sshoptions" | @SED@ 's/^-o[[:space:]]*/-o/')"

fi

### Cleanup options

if ! [ "$duplicity_major" -ge 0 -a "$duplicity_minor" -ge 6 -a "$duplicity_sub" -ge 20 ]; then

if ! version_ge "$duplicity_version" '0.6.20'; then

   execstr_options="${execstr_options} --extra-clean"

fi

# remove-all-inc-of-but-n-full : remove increments of older full backups : only keep latest ones

if [ "$keep" != "yes" ]; then

   if [ "$keepincroffulls" != "all" ]; then

      if [ "$duplicity_major" -ge 0 -a "$duplicity_minor" -ge 6 -a "$duplicity_sub" -ge 10 ]; then

      if version_ge "$duplicity_version" '0.6.10'; then

         debug "$execstr_precmd duplicity remove-all-inc-of-but-n-full $keepincroffulls --force $execstr_options $execstr_serverpart"

         if [ ! $test ]; then

            export PASSPHRASE=$password