Revert "debian: rules: Work around a regression in Autoconf 2.70."

This reverts commit 62f547b51ccf8d44af2ec2043e3fe69450632964.  The fix
now more properly lives in the contrib build system.

Change-Id: I7bb7d1f302c91be46627fc26eddece1d768fb308
diff --git a/packaging/rules/debian/rules b/packaging/rules/debian/rules
index 7ae0636..276f2f8 100755
--- a/packaging/rules/debian/rules
+++ b/packaging/rules/debian/rules
@@ -75,7 +75,7 @@
 	  --disable-natpmp  \
 	  --enable-gnutls $(BUNDLED_PKGS) && \
 	make list && \
-	GTKDOCIZE=true make -j$(NO_CPUS) V=1
+	make -j$(NO_CPUS) V=1
 	cd daemon && \
 	./autogen.sh && \
 	./configure \