aoe: clean up udev configuration example

This patch adds a known default location for the udev configuration file and
uses the more recent "==" syntax for SUBSYSTEM and KERNEL.

Signed-off-by: Ed L. Cashin <[e-mail]>
Cc: Greg KH <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

Documentation/aoe/udev-install.sh

···
 # /etc/udev/rules.d
 #
 rules_d="`sed -n '/^udev_rules=/{ s!udev_rules=!!; s!\"!!g; p; }' $conf`"
-if test -z "$rules_d" || test ! -d "$rules_d"; then
+if test -z "$rules_d" ; then
+	rules_d=/etc/udev/rules.d
+fi
+if test ! -d "$rules_d"; then
 	echo "$me Error: cannot find udev rules directory" 1>&2
 	exit 1
 fi

Documentation/aoe/udev.txt

···
 # These rules tell udev what device nodes to create for aoe support.
-# They may be installed along the following lines (adjusted to what
-# you see on your system).
+# They may be installed along the following lines.  Check the section
+# 8 udev manpage to see whether your udev supports SUBSYSTEM, and
+# whether it uses one or two equal signs for SUBSYSTEM and KERNEL.
 # 
 #   ecashin@makki ~$ su
 #   Password:
···
 #  
 
 # aoe char devices
-SUBSYSTEM="aoe", KERNEL="discover",	NAME="etherd/%k", GROUP="disk", MODE="0220"
-SUBSYSTEM="aoe", KERNEL="err",		NAME="etherd/%k", GROUP="disk", MODE="0440"
-SUBSYSTEM="aoe", KERNEL="interfaces",	NAME="etherd/%k", GROUP="disk", MODE="0220"
-SUBSYSTEM="aoe", KERNEL="revalidate",	NAME="etherd/%k", GROUP="disk", MODE="0220"
+SUBSYSTEM=="aoe", KERNEL=="discover",	NAME="etherd/%k", GROUP="disk", MODE="0220"
+SUBSYSTEM=="aoe", KERNEL=="err",	NAME="etherd/%k", GROUP="disk", MODE="0440"
+SUBSYSTEM=="aoe", KERNEL=="interfaces",	NAME="etherd/%k", GROUP="disk", MODE="0220"
+SUBSYSTEM=="aoe", KERNEL=="revalidate",	NAME="etherd/%k", GROUP="disk", MODE="0220"
 
 # aoe block devices     
-KERNEL="etherd*",       NAME="%k", GROUP="disk"
+KERNEL=="etherd*",       NAME="%k", GROUP="disk"