Don't clean tilda files in qubes-rpc

These are not created by build system, but by some editors. Developers
should deal with extra files created by theirs editors outside of build
files.

qubes-rpc/Makefile

@@ -25,7 +25,7 @@ qfile-unpacker: qfile-unpacker.o gui-fatal.o
 tar2qfile: tar2qfile.o gui-fatal.o
 
 clean:
-	-$(RM) qopen-in-vm qfile-agent qfile-unpacker tar2qfile vm-file-editor *.o *~
+	-$(RM) qopen-in-vm qfile-agent qfile-unpacker tar2qfile vm-file-editor *.o
 
 install:
 	install -d $(DESTDIR)$(BINDIR)