update libmariadb, and fix debian packaging for client libs

debian/libmariadb-dev.install

 usr/bin/mysql_config
-usr/include/mariadb
 usr/include/mysql/*.h
 usr/include/mysql/psi/*.h
 usr/lib/*/libmariadb.so

debian/libmariadb3.install

 usr/lib/*/libmariadbclient.so.*
 usr/lib/*/libmysqlclient.so.*
-usr/lib/mariadb/libmariadb.so.*
+usr/lib/*/libmariadb.so.*
 usr/lib/mysql/plugin/dialog.so
 usr/lib/mysql/plugin/mysql_clear_password.so

debian/rules

@@ -158,12 +158,12 @@ override_dh_auto_install:
 	install -D -m 644 debian/mariadb-server-10.2.py $(TMP)/usr/share/apport/package-hooks/source_mariadb-10.2.py
 
 	# Install libmariadbclient18 compatibility links
-	ln -s /usr/lib/mariadb/libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmariadbclient.so.18
+	ln -s $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmariadbclient.so.18
 
 	# Install libmysqlclientclientXX compatibility links
-	ln -s /usr/lib/mariadb/libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmysqlclient.so.18
-	ln -s /usr/lib/mariadb/libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmysqlclient.so.19
-	ln -s /usr/lib/mariadb/libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmysqlclient.so.20
+	ln -s $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmysqlclient.so.18
+	ln -s $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmysqlclient.so.19
+	ln -s $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmariadb.so.3 $(TMP)/usr/lib/$(DEB_HOST_MULTIARCH)/libmysqlclient.so.20
 
 	touch $@
 

libmariadb @ cae391f7

-Subproject commit 3837442cbc62c867198091b43dff40198fb6b762
+Subproject commit cae391f7bf47f17fb246cded8ddf0ef19dbfbdec