Suppressing memory leak in HistoryBackend::Init

tools/valgrind/memcheck/suppressions.txt

Index: tools/valgrind/memcheck/suppressions.txt
diff --git a/tools/valgrind/memcheck/suppressions.txt b/tools/valgrind/memcheck/suppressions.txt
index d1745edb393e30614fa7f2d7d013ecaeb648b57f..4328fbda936f472a7cd22bc0ebe51add26dc90c0 100644
--- a/tools/valgrind/memcheck/suppressions.txt
+++ b/tools/valgrind/memcheck/suppressions.txt
@@ -3543,3 +3543,18 @@
    fun:_ZN11MessageLoop11RunInternalEv
    fun:_ZN11MessageLoop10RunHandlerEv
 }
+{
+   bug_50304
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZNSs4_Rep9_S_createEjjRKSaIcE
+   fun:_ZNSs4_Rep8_M_cloneERKSaIcEj
+   fun:_ZNSs7reserveEj
+   fun:_ZNSs6appendEjc
+   fun:_ZNK8FilePath6AppendERKSs
+   fun:_ZNK7history14HistoryBackend*FileNameEv
+   fun:_ZN7history14HistoryBackend8InitImplEv
+   fun:_ZN7history14HistoryBackend4InitEb
+   fun:_Z16DispatchToMethodIN7history14HistoryBackendEMS1_FvbEbEvPT_T0_RK6Tuple1IT1_E
+   fun:_ZN14RunnableMethodIN7history14HistoryBackendEMS1_FvbE6Tuple1IbEE3RunEv
+}