remove unused patch

unused since...

commit 8dfe1a17
Author: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>
Date:   Thu Jul 30 21:57:11 2015 +0200

    fix firebird build on Win64

Change-Id: I8041e39bde3f03da71a5cd8b2edf4af3f887a6d5

external/firebird/firebird-vs2013.patch.1

---- firebird/src/jrd/os/win32/mod_loader.cpp.orig       2015-06-05 07:18:34.639613335 +0300
-+++ firebird/src/jrd/os/win32/mod_loader.cpp    2015-06-05 07:41:08.383489041 +0300
-@@ -97,6 +97,8 @@
-                     "msvcr100.dll",
- #elif _MSC_VER == 1700
-                     "msvcr110.dll",
-+#elif _MSC_VER == 1800
-+                     "mscvr120.dll",
- #else
-                     #error Specify CRT DLL name here !
- #endif