Add fs_config support for vendor_boot

Test:
1) add META/vendor_boot_filesystem_config.txt to    merge_config_other_item_list
2)Building vendor_boot image from target_files

Change-Id: Ia983d1119e30c46a6730566c567f13e25a65b0ff
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 2367691..d91a713 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -1971,7 +1971,7 @@
   return None
 
 
-def _BuildVendorBootImage(sourcedir, partition_name, info_dict=None):
+def _BuildVendorBootImage(sourcedir, fs_config_file, partition_name, info_dict=None):
   """Build a vendor boot image from the specified sourcedir.
 
   Take a ramdisk, dtb, and vendor_cmdline from the input (in 'sourcedir'), and
@@ -1987,7 +1987,7 @@
   img = tempfile.NamedTemporaryFile()
 
   ramdisk_format = GetRamdiskFormat(info_dict)
-  ramdisk_img = _MakeRamdisk(sourcedir, ramdisk_format=ramdisk_format)
+  ramdisk_img = _MakeRamdisk(sourcedir, fs_config_file=fs_config_file, ramdisk_format=ramdisk_format)
 
   # use MKBOOTIMG from environ, or "mkbootimg" if empty or not set
   mkbootimg = os.getenv('MKBOOTIMG') or "mkbootimg"
@@ -2101,8 +2101,9 @@
   if info_dict is None:
     info_dict = OPTIONS.info_dict
 
+  fs_config = "META/" + tree_subdir.lower() + "_filesystem_config.txt"
   data = _BuildVendorBootImage(
-      os.path.join(unpack_dir, tree_subdir), "vendor_boot", info_dict)
+      os.path.join(unpack_dir, tree_subdir), os.path.join(unpack_dir, fs_config), "vendor_boot", info_dict)
   if data:
     return File(name, data)
   return None
@@ -2126,7 +2127,7 @@
     info_dict = OPTIONS.info_dict
 
   data = _BuildVendorBootImage(
-      os.path.join(unpack_dir, tree_subdir), "vendor_kernel_boot", info_dict)
+      os.path.join(unpack_dir, tree_subdir), None, "vendor_kernel_boot", info_dict)
   if data:
     return File(name, data)
   return None