Configure: moved NGX_SBIN_PATH variable initialization.

It's now initialized in auto/options like the rest of variables
for system paths.

As a side effect, the currently unused macro NGX_SBIN_PATH now
gets the correct value.

auto/install

@@ -20,10 +20,6 @@ case ".$NGX_SBIN_PATH" in
     ./*)
     ;;
 
-    .)
-        NGX_SBIN_PATH=$NGX_PREFIX/sbin/nginx
-    ;;
-
     *)
         NGX_SBIN_PATH=$NGX_PREFIX/$NGX_SBIN_PATH
     ;;

auto/options

@@ -525,6 +525,7 @@ if [ ".$NGX_PLATFORM" = ".win32" ]; then
 fi
 
 
+NGX_SBIN_PATH=${NGX_SBIN_PATH:-sbin/nginx}
 NGX_CONF_PATH=${NGX_CONF_PATH:-conf/nginx.conf}
 NGX_CONF_PREFIX=`dirname $NGX_CONF_PATH`
 NGX_PID_PATH=${NGX_PID_PATH:-logs/nginx.pid}