Explicitly depend on fb_sysfs in fb_storage (#240)

Summary:
I spun up a new class of GCE VM which uses NVMe-based storage, but fb_storage failed, complaining about being unable to find fb_sysfs. After digging into it a bit, I noticed that fb_storage doesn't explicitly depend on `fb_sysfs`, despite using it in several places, [like when configuring nvme-based storage](https://github.com/facebook/chef-cookbooks/blob/c64381a2e0195855703f59a001a64a589ae1ac73/cookbooks/fb_storage/resources/format_devices.rb#L169).

I verified that simply adding `depends 'fb_sysfs'` was enough to resolve the error.

Pull Request resolved: #240

Differential Revision: D60453758

fbshipit-source-id: 35e7b57bdecf37a1a27311004cd5cb66df70d1b6

cookbooks/fb_storage/metadata.rb

@@ -9,3 +9,4 @@
 version '0.0.1'
 supports 'centos'
 depends 'fb_helpers'
+depends 'fb_sysfs'