doc: fix version parsing

copyright = u'2015-2017 Zephyr Project members and individual contributors.'

author = u'many'

if "ZEPHYR_BASE" not in os.environ:

    sys.stderr.write("$ZEPHYR_BASE environment variable undefined.\n")

    exit(1)

ZEPHYR_BASE = os.environ["ZEPHYR_BASE"]

# The following code tries to extract the information by reading the Makefile,

# when Sphinx is run directly (e.g. by Read the Docs).

    version_minor = None

    patchlevel = None

    extraversion = None

    for line in open('../VERSION'):

    for line in open(os.path.join(ZEPHYR_BASE, 'VERSION')):

        key, val = [x.strip() for x in line.split('=', 2)]

        if key == 'VERSION_MAJOR':

            version_major = val

except:

    pass

finally:

    if version_major and version_minor and patchlevel and extraversion:

    if version_major and version_minor and patchlevel and extraversion is not None :

        version = release = version_major + '.' + version_minor + '.' + patchlevel

        if extraversion != '':

            version = release = version + '-' + extraversion