635878: wireshark supplied filter manpage is empty

tshark as executed by doc/Makefile tends to link with existing libraries in
/usr/lib instead of just compiled libraries.

Point the linker to the right place using LD_LIBRARY_PATH.

diff -up wireshark-1.4.0/doc/Makefile.in.orig wireshark-1.4.0/doc/Makefile.in
--- wireshark-1.4.0/doc/Makefile.in.orig	2010-08-30 00:19:25.000000000 +0200
+++ wireshark-1.4.0/doc/Makefile.in	2010-09-24 14:54:47.857565183 +0200
@@ -835,7 +835,7 @@ wireshark-filter.html: wireshark-filter.
 	wireshark-filter.pod > wireshark-filter.html
 
 wireshark-filter.pod: wireshark-filter.pod.template  ../tshark
-	WIRESHARK_RUN_FROM_BUILD_DIRECTORY=1 ../tshark -G fields | \
+	WIRESHARK_RUN_FROM_BUILD_DIRECTORY=1 LD_LIBRARY_PATH=../epan/.libs ../tshark -G fields | \
 	$(PERL) $(srcdir)/dfilter2pod.pl $(srcdir)/wireshark-filter.pod.template > wireshark-filter.pod
 
 capinfos.1: capinfos.pod ../config.h