libports: download location of jbig2dec

The original git:// URL produced the following error:

Cloning into 'jbig2dec'...
fatal: remote error: access denied or repository not exported: /jbig2dec.git

repos/libports/ports/jbig2dec.hash

@@ -1 +1 @@
-9d2c3e8a2347b80c45b39810d74c5977ef0cc228
+4ccfffd8e6b8f3e5fb5b8aeaa219e9547c6323a1

repos/libports/ports/jbig2dec.port

@@ -2,7 +2,7 @@ LICENSE := unknown
 DOWNLOADS := jbig2dec.git
 VERSION := 0.11
 
-URL(jbig2dec) := git://git.ghostscript.com/jbig2dec.git
+URL(jbig2dec) := http://git.ghostscript.com/jbig2dec.git
 REV(jbig2dec) := 58b513e3ec60feac13ea429c4aff12ea8a8de91d
 DIR(jbig2dec) := src/lib/jbig2dec