libports: prevent main symbol clash in fuse-ext2

Omit the main rountine in fuse-ext2.c. Otherwise using fuse-ext2 with
fuse_fs is not possible because the server framework already defines
a main routine.

Fixes #1058.

libports/src/lib/fuse-ext2/patches/fuse-ext2.c.patch

@@ -1,5 +1,5 @@
---- contrib/fuse-ext2-svn-220/fuse-ext2/fuse-ext2.c.orig	2013-11-22 17:13:24.484906614 +0100
-+++ contrib/fuse-ext2-svn-220/fuse-ext2/fuse-ext2.c	2013-11-22 17:13:35.520907100 +0100
+--- contrib/fuse-ext2-svn-220/fuse-ext2/fuse-ext2.c.orig	2013-11-27 17:49:58.000000000 +0100
++++ contrib/fuse-ext2-svn-220/fuse-ext2/fuse-ext2.c	2013-11-27 17:50:45.593877786 +0100
 @@ -278,7 +278,7 @@
  	goto exit;
  }
@@ -9,3 +9,16 @@
  	.getattr        = op_getattr,
  	.readlink       = op_readlink,
  	.mknod          = op_mknod,
+@@ -317,6 +317,7 @@
+ 	.bmap           = NULL,
+ };
+ 
++#if 0
+ int main (int argc, char *argv[])
+ {
+ 	int err = 0;
+@@ -385,3 +386,4 @@
+ 	free(opts.volname);
+ 	return err;
+ }
++#endif