remove 'hack' for mysql (Makefile.am)

extensions/DBServer-MySQL/Makefile.am

@@ -7,7 +7,6 @@ UMYSQL_VER=@LIBVER@
 lib_LTLIBRARIES 			= libUniSet-mysql.la
 libUniSet_mysql_la_LDFLAGS  = -version-info $(UMYSQL_VER) 
 libUniSet_mysql_la_SOURCES	= DBInterface.cc DBServer_MySQL.cc
-libUniSet_mysql_la_CXXFLAGS = -L/usr/lib/mysql
 libUniSet_mysql_la_LIBADD	= $(top_builddir)/lib/libUniSet.la -lmysqlclient
 
 bin_PROGRAMS 					= uniset-mysql-dbserver