Uniformize SUBR_DIR quoting

It needs to be quoted when used as an argument. Putting the name in curly braces is unnecessary.

scripts/netcfg-wpa_actiond

 #! /bin/bash
 . /usr/lib/network/network
-. $SUBR_DIR/8021x
-. $SUBR_DIR/rfkill
+. "$SUBR_DIR/8021x"
+. "$SUBR_DIR/rfkill"
 . /etc/rc.conf
 . /etc/conf.d/netcfg
 

scripts/wifi-menu

 #! /bin/bash
 
 . /usr/lib/network/network
-. $SUBR_DIR/8021x
+. "$SUBR_DIR/8021x"
 . /etc/conf.d/netcfg
 
 # The right value depends on the connected profile.

src-wireless/netcfg-auto-wireless

@@ -2,8 +2,8 @@
 # Originally contributed by Neuro: http://bbs.archlinux.org/viewtopic.php?pid=278148#p278148
 
 . /usr/lib/network/network
-. $SUBR_DIR/rfkill
-. $SUBR_DIR/8021x
+. "$SUBR_DIR/rfkill"
+. "$SUBR_DIR/8021x"
 . /etc/conf.d/netcfg
 
 # wifi_auto

src/connections/wireless

 #! /bin/bash
 . /usr/lib/network/network
-. $SUBR_DIR/8021x
-. $SUBR_DIR/rfkill
+. "$SUBR_DIR/8021x"
+. "$SUBR_DIR/rfkill"
 
 wireless_up() {
 

src/globals

@@ -12,8 +12,8 @@
 PROFILE_DIR="/etc/network.d"
 IFACE_DIR="$PROFILE_DIR/interfaces"
 SUBR_DIR="/usr/lib/network"
-HOOKS_DIR="${SUBR_DIR}/hooks"
-CONN_DIR="${SUBR_DIR}/connections"
+HOOKS_DIR="$SUBR_DIR/hooks"
+CONN_DIR="$SUBR_DIR/connections"
 STATE_DIR="/run/network"