imagelib: Get rid of the now unused ChromeosVersion wrapper.

Since the build_image tool no longer extracts the ChromeOS version string
itself, it no longer needs this wrapper.

Change-Id: Ibae7d06b0ad11b37decc6ee45d310a106f99a327
diff --git a/src/image/imagelib/tools/ChromeosVersion.py b/src/image/imagelib/tools/ChromeosVersion.py
deleted file mode 100644
index e0bbd19..0000000
--- a/src/image/imagelib/tools/ChromeosVersion.py
+++ /dev/null
@@ -1,32 +0,0 @@
-# Copyright 2016 Google Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from Tool import Tool
-
-import re
-
-class ChromeosVersion(Tool):
-    def __init__(self, verbose=False):
-        super(ChromeosVersion, self).__init__(verbose)
-
-    def get(self):
-        ret, stdout = self.run(["bash", "-c", "chromeos_version.sh"])
-        if ret != 0:
-            raise RuntimeError("chromeos_version.sh failed:\n%s" % stdout)
-
-        pairs = re.findall(r"([A-Za-z_]*)=(.*)", stdout)
-        version_vars = {}
-        for pair in pairs:
-            version_vars[pair[0]] = pair[1]
-        return version_vars