contrib: remove unused sqlite

It's not built by default.
It doesn't seem to be force built by libvlcjni or medialibrary either.

contrib/src/sqlite/SHA512SUMS

-fd6761a6c8f76d137cc8c98b8ae77f8f4206dbf187d66e324f7dc6a79eb752d441446139216eadb534cf5601345c2ea1da3312305e24c762b6e16318cf4adb5e  sqlite-3.6.20.tar.gz

contrib/src/sqlite/rules.mak

-# sqlite
-
-SQLITE_VERSION := 3.6.20
-SQLITE_URL := http://www.sqlite.org/sqlite-amalgamation-$(SQLITE_VERSION).tar.gz
-
-# PKGS += sqlite
-
-ifeq ($(call need_pkg,"sqlite3"),)
-PKGS_FOUND += sqlite
-endif
-
-$(TARBALLS)/sqlite-$(SQLITE_VERSION).tar.gz:
-	$(call download_pkg,$(SQLITE_URL),sqlite)
-
-.sum-sqlite: sqlite-$(SQLITE_VERSION).tar.gz
-
-sqlite: sqlite-$(SQLITE_VERSION).tar.gz .sum-sqlite
-	$(UNPACK)
-	$(MOVE)
-
-.sqlite: sqlite
-	cd $< && $(HOSTVARS) ./configure $(HOSTCONF)
-	cd $< && $(MAKE) && $(MAKE) install
-	touch $@