Fix path conflict for vendor_ramdisk_available

... and ramdisk_available modules. If a module is both
vendor_ramdisk_available and ramdisk_available, on a device
that mark recovery_as_boot and move_recovery_resources_to_vendor_boot
simultaneously (and incorrectly),
both will be installed to recovery/root/first_stage_ramdisk. Fix the
path conflict of the two variants by moving the vendor_ramdisk variant
to vendor-ramdisk/first_stage_ramdisk instead.

Also update comments for Vendor_ramdisk_available.

Test: m nothing -j
Bug: 156098440

Change-Id: I2b776b6fd8f5a2c361c0f6a89231e3cebc2646f0
diff --git a/sh/sh_binary.go b/sh/sh_binary.go
index 6f40ae4..7e5c344 100644
--- a/sh/sh_binary.go
+++ b/sh/sh_binary.go
@@ -66,9 +66,17 @@
 	Symlinks []string `android:"arch_variant"`
 
 	// Make this module available when building for ramdisk.
+	// On device without a dedicated recovery partition, the module is only
+	// available after switching root into
+	// /first_stage_ramdisk. To expose the module before switching root, install
+	// the recovery variant instead.
 	Ramdisk_available *bool
 
 	// Make this module available when building for vendor ramdisk.
+	// On device without a dedicated recovery partition, the module is only
+	// available after switching root into
+	// /first_stage_ramdisk. To expose the module before switching root, install
+	// the recovery variant instead.
 	Vendor_ramdisk_available *bool
 
 	// Make this module available when building for recovery.