Fuchsia: Fix bugs in incremental packaged deployment

1. Target.IsNewInstance() was returning to true when host name is
specified explicitly. This is incorrect because the host is expected to
be provisioned and it may be reused for multiple test runs.
2. Updated deployment code to read /blob instead of /blobstore to get
list of existing blobs.

Bug: 798851
Change-Id: I62b04a352a364250e2aa2d44319494481be011c6
Reviewed-on: https://chromium-review.googlesource.com/956349
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541975}

build/fuchsia/runner_v2/device_target.py

@@ -40,6 +40,7 @@ class DeviceTarget(target.Target):
       self._host = host
       if port:
         self._port = port
+      self._new_instance = False
 
   def __Discover(self, node_name):
     """Returns the IP address and port of a Fuchsia instance discovered on

build/fuchsia/runner_v2/run_package.py

@@ -22,7 +22,7 @@ PM = os.path.join(common.SDK_ROOT, 'tools', 'pm')
 
 def _Deploy(target, output_dir, archive_path):
   """Converts the FAR archive at |archive_path| into a Fuchsia package
-  and deploys it to |target|'s blobstore. If |incremental| is set,
+  and deploys it to |target|'s blobstore. If target.IsNewInstance() is not set,
   then the remote target's blobstore is queried and only the changed blobs
   are copied.
 
@@ -71,7 +71,7 @@ def _Deploy(target, output_dir, archive_path):
     existing_blobs = set()
     if not target.IsNewInstance():
       logging.debug('Querying the target blobstore\'s state.')
-      ls = target.RunCommandPiped(['ls', '/blobstore'], stdout=subprocess.PIPE)
+      ls = target.RunCommandPiped(['ls', '/blob'], stdout=subprocess.PIPE)
       for blob in ls.stdout:
         existing_blobs.add(blob.strip())
       ls.wait()
@@ -123,7 +123,6 @@ def _Deploy(target, output_dir, archive_path):
 
         'rm', '/tmp/meta.far'])
 
-
     if result != 0:
       raise Exception('Deployment failed.')