init: remove dependency on spack.version

- no longer require `spack_version` to be a Version (it isn't used that
  way anyway)

- use a simple tuple `spack_version_info` with major, minor, patch
  versions

- generate `spack_version` from the tuple

lib/spack/docs/conf.py

@@ -192,9 +192,9 @@ def setup(sphinx):
 # built documents.
 #
 # The short X.Y version.
-version = str(spack.spack_version.up_to(2))
+version = '.'.join(str(s) for s in spack.spack_version_info[:2])
 # The full version, including alpha/beta/rc tags.
-release = str(spack.spack_version.up_to(2))
+release = spack.spack_version
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.

lib/spack/spack/__init__.py

@@ -25,19 +25,11 @@
 ##############################################################################
 import sys
 
-#-----------------------------------------------------------------------------
-# Initialize various data structures & objects at the core of Spack.
-#
-# TODO: move all of these imports out of __init__ to avoid importing the whole
-# TODO: world on Spack startup. There are some design changes that need to be
-# TODO: made to enable this (decoupling Spec, repo, DB, and store state).
-#
-# TODO: Spack probably needs some kind of object to manage this state so that
-# TODO: this stuff doesn't have to be at module scope.
-# -----------------------------------------------------------------------------
-# Version information
-from spack.version import Version
-spack_version = Version("0.11.2")
+#: major, minor, patch version for Spack, in a tuple
+spack_version_info = (0, 11, 2)
+
+#: String containing Spack version joined with .'s
+spack_version = '.'.join(str(v) for v in spack_version_info)
 
 
 # Set up the default packages database.

lib/spack/spack/test/cmd/python.py

@@ -30,4 +30,4 @@
 
 def test_python():
     out = python('-c', 'import spack; print(spack.spack_version)')
-    assert out.strip() == str(spack.spack_version)
+    assert out.strip() == spack.spack_version