debian packaging: don't build contrib with -j2

Building contrib in parallel seems to occasionally cause issues.

Tuleap: #783
Change-Id: I938f54a47ddea8b69f21210471a0fa2d69ce6a1f

debian/rules

@@ -17,7 +17,9 @@ export DH_VERBOSE=1
 	dh $@
 
 override_dh_auto_configure:
-	mkdir -p contrib/native && cd contrib/native && ../bootstrap --disable-ogg --disable-flac --disable-vorbis --disable-vorbisenc --disable-speex --disable-sndfile --disable-speexdsp && make list && make -j 2
+	mkdir -p contrib/native && cd contrib/native && ../bootstrap --disable-ogg --disable-flac \
+	--disable-vorbis --disable-vorbisenc --disable-speex --disable-sndfile --disable-speexdsp \
+	&& make list && make
 	@echo "Contribs built"
 	#./autogen.sh && ./configure --prefix=/usr --with-contrib=yes CFLAGS="$(CFLAGS) -fPIC" LDFLAGS="-Wl,-z,defs"
 	./autogen.sh && ./configure --prefix=/usr