Rename the Fuchsia SDK SHA1 file for Linux.

For consistency across platforms, the file has been renamed.

Bug: 707030
Test: Local
Change-Id: I18eb37e562a4b3d9946152b0f1153ba113cb340a
Reviewed-on: https://chromium-review.googlesource.com/1196890
Commit-Queue: Fabrice de Gans-Riberi <fdegans@chromium.org>
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587637}

build/fuchsia/update_sdk.py

@@ -25,10 +25,8 @@ SDK_SUBDIRS = ["arch", "pkg", "qemu", "sysroot", "target",
                "toolchain_libs", "tools"]
 
 def GetSdkHashForPlatform():
-  if sys.platform.startswith('darwin'):
-    return os.path.join(os.path.dirname(__file__), 'mac.sdk.sha1')
-  else:
-    return os.path.join(os.path.dirname(__file__), 'sdk.sha1')
+  filename = '{platform}.sdk.sha1'.format(platform =  GetHostOsFromPlatform())
+  return os.path.join(os.path.dirname(__file__), filename)
 
 def GetBucketForPlatform():
   return 'gs://fuchsia/sdk/{platform}-amd64/'.format(