remove obsolete and already broken subst

mysql/mysql.spec

@@ -90,10 +90,6 @@ AutoReqProv:  no
     %patch -p0
 
 %build
-    #   patch file search path
-    %{l_shtool} subst %{l_value -s -a} \
-        mysys/default.c
-
     #   determine additional configure options
     case "%{l_platform -t}" in
         *-freebsd* ) opt="--with-client-ldflags=-static --with-mysqld-ldflags=-static" ;;