gnu: Remove deleted patch file from build system.

* gnu-system.am (dist_patch_DATA): Remove 'gnu/packages/patches/librep-rules.mk.patch'.

gnu-system.am

@@ -461,7 +461,6 @@ dist_patch_DATA =						\
   gnu/packages/patches/libevent-dns-tests.patch			\
   gnu/packages/patches/liboop-mips64-deplibs-fix.patch		\
   gnu/packages/patches/libmad-mips-newgcc.patch			\
-  gnu/packages/patches/librep-rules.mk.patch			\
   gnu/packages/patches/libtheora-config-guess.patch		\
   gnu/packages/patches/libtool-skip-tests.patch			\
   gnu/packages/patches/libssh-CVE-2014-0017.patch		\