net/transmission: Refresh patches and minor tweaks

Refresh patches
Add patch to spoof git-version as release
Switch to xz tarball

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>

net/transmission/patches/020-use-internal-miniupnp.patch

@@ -1,6 +1,6 @@
 --- a/configure.ac
 +++ b/configure.ac
-@@ -378,7 +378,7 @@ dnl See if ANY version of miniupnpc is i
+@@ -386,7 +386,7 @@ dnl See if ANY version of miniupnpc is i
  AC_LINK_IFELSE(
    [AC_LANG_PROGRAM([#include <miniupnpc/miniupnpc.h>],
                     [struct UPNPDev dev;])],