configure: Require Python 2.6

RHEL-6 and SLES-11 provide Python 2.6.  It'll also work on OS X back
to 10.6.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <1441396383-17304-1-git-send-email-armbru@redhat.com>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

configure

@@ -1166,18 +1166,14 @@ fi
 
 # Note that if the Python conditional here evaluates True we will exit
 # with status 1 which is a shell 'false' value.
-if ! $python -c 'import sys; sys.exit(sys.version_info < (2,4) or sys.version_info >= (3,))'; then
-  error_exit "Cannot use '$python', Python 2.4 or later is required." \
+if ! $python -c 'import sys; sys.exit(sys.version_info < (2,6) or sys.version_info >= (3,))'; then
+  error_exit "Cannot use '$python', Python 2.6 or later is required." \
       "Note that Python 3 or later is not yet supported." \
       "Use --python=/path/to/python to specify a supported Python."
 fi
 
-# The -B switch was added in Python 2.6.
-# If it is supplied, compiled files are not written.
-# Use it for Python versions which support it.
-if $python -B -c 'import sys; sys.exit(0)' 2>/dev/null; then
-  python="$python -B"
-fi
+# Suppress writing compiled files
+python="$python -B"
 
 case "$cpu" in
     ppc)