cros deploy: simplify _GetPackagesPaths implementation

The |pkgs| variable passed into _GetPackagesPaths contain only cpvs*, so
simplify its implementation based on that.

*pkgs comes from pkg_scanner.Run(..), which supposed to return the cpvs
string (see cs/chromeos_public/chromite/cli/deploy.py?rcl=c08d404a452b5d55b99fb665ace0435ba4d6e198&l=679)

BUG=chromium:920140
TEST=unittest, run `cros deploy` locally

Change-Id: I93784b88f3d79436829270dec7dc1af4a3397ea0
Reviewed-on: https://chromium-review.googlesource.com/1484191
Commit-Ready: Ned Nguyen <nednguyen@google.com>
Tested-by: Ned Nguyen <nednguyen@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/cli/deploy.py b/cli/deploy.py
index 1090f66..533ebce 100644
--- a/cli/deploy.py
+++ b/cli/deploy.py
@@ -838,30 +838,16 @@
 def _GetPackagesPaths(pkgs, strip, sysroot):
   """Returns paths to binary |pkgs|.
 
-  Each package argument may be specified as a filename, in which case it is
-  returned as-is, or it may be a CPV value, in which case it is stripped (if
-  instructed) and a path to it is returned.
-
   Args:
-    pkgs: List of package arguments.
+    pkgs: List of package CPVs string.
     strip: Whether or not to run strip_package for CPV packages.
     sysroot: The sysroot path.
 
   Returns:
     List of paths corresponding to |pkgs|.
   """
-  indexes = []
-  cpvs = []
-  for i, pkg in enumerate(pkgs):
-    if not os.path.isfile(pkg):
-      indexes.append(i)
-      cpvs.append(portage_util.SplitCPV(pkg))
-
-  cpv_paths = cpvs and _GetPackagesByCPV(cpvs, strip, sysroot)
-  paths = list(pkgs)
-  for i, cpv_path in zip(indexes, cpv_paths):
-    paths[i] = cpv_path
-  return paths
+  cpvs = [portage_util.SplitCPV(p) for p in pkgs]
+  return _GetPackagesByCPV(cpvs, strip, sysroot)
 
 
 def _Unmerge(device, pkg, root):