[packages] mysql: fix /bin/hostname invocation in table install script, openwrt does not have this command

git-svn-id: svn://svn.openwrt.org/openwrt/packages@25182 3c298f89-4303-0410-b956-a3cf2f4a3e73

libs/mysql/patches/502-fix-hostname.patch

@@ -0,0 +1,11 @@
+--- a/scripts/mysql_install_db.sh
++++ b/scripts/mysql_install_db.sh
+@@ -317,7 +317,7 @@ then
+ fi
+ 
+ # Try to determine the hostname
+-hostname=`@HOSTNAME@`
++hostname=`cat /proc/net/hostname`
+ 
+ # Check if hostname is valid
+ if test "$cross_bootstrap" -eq 0 -a "$in_rpm" -eq 0 -a "$force" -eq 0