remove unused patch miniupnpc-build-1.patch

It is not used after eb20723302,
in which Makefile based installation was replaced with CMake
based installation.

See https://github.com/mxe/mxe/issues/1051#issuecomment-164201749

src/miniupnpc-build-1.patch

@@ -1,28 +0,0 @@
---- ./Makefile.mingw	2014-01-31 14:18:56.000000000 +0100
-+++ ./Makefile.mingw.new	2015-04-27 15:44:59.548000000 +0200
-@@ -37,7 +37,7 @@
- 	$(PYTHON) setupmingw32.py install --skip-build
- 
- miniupnpc.dll:	libminiupnpc.a $(OBJSDLL)
--	dllwrap -k --driver-name gcc \
-+	$(DLLWRAP) -k --driver-name $(CC) \
- 	--def miniupnpc.def \
- 	--output-def miniupnpc.dll.def \
- 	--implib miniupnpc.lib -o $@ \
-@@ -71,13 +71,13 @@
- miniupnpcstrings.h: miniupnpcstrings.h.in wingenminiupnpcstrings
- 	wingenminiupnpcstrings $< $@
- 
--minixml.o:	minixml.c minixml.h miniupnpcstrings.h
-+minixml.o:	minixml.c minixml.h
- 
- upnpc.o:	upnpc.c miniwget.h minisoap.h miniupnpc.h igd_desc_parse.h upnpreplyparse.h upnpcommands.h upnperrors.h
- 
--miniwget.o:	miniwget.c miniwget.h miniupnpcstrings.h connecthostport.h
-+miniwget.o:	miniwget.c miniwget.h connecthostport.h
- 
--minisoap.o:	minisoap.c minisoap.h miniupnpcstrings.h
-+minisoap.o:	minisoap.c minisoap.h
- 
- miniupnpc.o:	miniupnpc.c miniupnpc.h minisoap.h miniwget.h minixml.h
-