Fix wssshtools Debian package build - missing /usr/sbin directory

- Added mkdir command to create /usr/sbin directory in debian/rules
- Fixed 'No such file or directory' error when installing wssshc-watchdog
- Ensures proper directory structure for watchdog script installation
- Resolves build failure when running build.sh --packages or --debian-only
- Maintains consistency with other directory creation commands

wssshtools/debian/rules

@@ -31,6 +31,7 @@ override_dh_auto_install:
 	mkdir -p debian/wsssh-tools/usr/share/wsssh
 	mkdir -p debian/wsssh-tools/etc/default
 	mkdir -p debian/wsssh-tools/usr/bin
+	mkdir -p debian/wsssh-tools/usr/sbin
 
 	# Install wssshc init script
 	install -m 755 ../wssshc.init debian/wsssh-tools/etc/init.d/wssshc