Expose xccdf_policy_get_value_of_item as public API
Correctly skip "Signature" when parsing sds_index without spewing out an error
rhbz#1084067: Make sure the OVAL session is created before using it

Addressing segfault:
 #0  oval_agent_eval_definition (ag_sess=0x0, id=0x7f0513727580 "oval:org.open-scap.cpe.rhel:def:6") at oval_agent.c:160
 #1  0x00007f0512638fb1 in _xccdf_policy_cpe_check_cb (sys=<value optimized out>, href=0x7f051367b6c0 "openscap-cpe-oval.xml",
     name=0x7f0513727580 "oval:org.open-scap.cpe.rhel:def:6", usr=<value optimized out>) at xccdf_policy.c:823
 #2  0x00007f0512616b54 in cpe_check_evaluate (item=<value optimized out>, cb=0x7f0512638f00 <_xccdf_policy_cpe_check_cb>, usr=0x7f0513670940) at cpedict.c:173
 #3  cpe_item_is_applicable (item=<value optimized out>, cb=0x7f0512638f00 <_xccdf_policy_cpe_check_cb>, usr=0x7f0513670940) at cpedict.c:183
 #4  0x00007f0512616c0c in cpe_name_applicable_dict (cpe=0x7f0513670800, dict=<value optimized out>, cb=0x7f0512638f00 <_xccdf_policy_cpe_check_cb>, usr=0x7f0513670940)
     at cpedict.c:157
 #5  0x00007f05126391af in xccdf_policy_model_platforms_are_applicable_dict (model=0x7f051366bb20, dict=0x7f0513676960, platforms=0x7f05136707a0) at xccdf_policy.c:880
 #6  0x00007f0512639322 in xccdf_policy_model_platforms_are_applicable (model=0x7f051366bb20, platforms=0x7f05136707a0) at xccdf_policy.c:972
trac#378: Return non-zero when cannot resolve XCCDF.

Regression, brought by 7363256124d414
Consider the last set-value as the effective set-value

This makes openscap behave correctly in cases where there are more
set-values setting the same item. While this is forbidden in serialized
content it makes sense to create such content via the API.
Only export the effective set-value in each profile

Otherwise we may end up with invalid content being exported.
Export set-value in TestResult correctly
Cast enums to int before comparing them to 0 in xccdf_policy.c

Pointed out by Jacob Varughese, thanks!
Export results only after evaluation

Addressing (Segmentation Fault):
libopenscap_testing.so(+0xd2674) [0x7f87337ab674] item.c:176
libopenscap_testing.so(xccdf_result_clone+0x4e) [0x7f87337b88bb] result.c:78
libopenscap_testing.so(xccdf_session_export_xccdf+0xe3) [0x7f87337c4fd3] xccdf_session.c:991
tests: Skip test when libxml 2.7.6-14 is around

Addressing false negative:
$ echo 2.7.6-14.el6 |  awk -F. '{print ($1 == 2 && ($2 < 7 || ($2 == 7 && $3 <= 6))) ? "true" : "false"}'
false

Fixed:
$ echo 2.7.6-14.el6 |  awk -F. '{print ($1 == 2 && ($2 < 7 || ($2 == 7 && $3 < 7))) ? "true" : "false"}'
true
tests: Take only one of the installed versions for comparison.

Addressing:
version=2.7.62.7.6 on multilib systems
Merge branch 'maint-1.0'
Display severity, weight in summary section
trac#384: Report when has_extended_acl does not exist correctly