Add OVAL check for GDM login banner

- Adds OVAL check for GDM Login Banner text
new remediation: accounts_password_pam_cracklib_dcredit.sh
new remediation: display_login_attempts.sh
New OVAL + Remediation for accounts_password_pam_cracklib_maxrepeat

testing evidence:
[root@ssg-rhel6-devbox checks]# var_password_pam_cracklib_maxrepeat=3; export var_password_pam_cracklib_maxrepeat
[root@ssg-rhel6-devbox checks]# ./testcheck.py accounts_password_pam_cracklib_maxrepeat.xml
external_variable with id : var_password_pam_cracklib_maxrepeat
Evaluating with OVAL tempfile : /tmp/accounts_password_pam_cracklib_maxrepeatHsM_Zr.xml
Writing results to : /tmp/accounts_password_pam_cracklib_maxrepeatHsM_Zr.xml-results
Definition oval:scap-security-guide.testing:def:138: false
Evaluation done.
[root@ssg-rhel6-devbox checks]# grep maxrepeat /etc/pam.d/system-auth
[root@ssg-rhel6-devbox checks]# cd ../fixes/bash/
[root@ssg-rhel6-devbox bash]# bash accounts_password_pam_cracklib_maxrepeat.sh
[root@ssg-rhel6-devbox bash]# cd -
/var/www/html/gh/scap-security-guide/RHEL/6/input/checks
[root@ssg-rhel6-devbox checks]# ./testcheck.py accounts_password_pam_cracklib_maxrepeat.xml
external_variable with id : var_password_pam_cracklib_maxrepeat
Evaluating with OVAL tempfile : /tmp/accounts_password_pam_cracklib_maxrepeatW0rRbK.xml
Writing results to : /tmp/accounts_password_pam_cracklib_maxrepeatW0rRbK.xml-results
Definition oval:scap-security-guide.testing:def:138: true
Evaluation done.
[root@ssg-rhel6-devbox checks]# grep maxrepeat /etc/pam.d/system-auth
password    requisite     pam_cracklib.so try_first_pass retry=3 type= dcredit=-1 maxrepeat=3
[root@ssg-rhel6-devbox checks]# sed -i --follow-symlinks 's/maxrepeat=3/maxrepeat=500/g' /etc/pam.d/system-auth
[root@ssg-rhel6-devbox checks]# ./testcheck.py accounts_password_pam_cracklib_maxrepeat.xml
external_variable with id : var_password_pam_cracklib_maxrepeat
Evaluating with OVAL tempfile : /tmp/accounts_password_pam_cracklib_maxrepeatZlo4Ro.xml
Writing results to : /tmp/accounts_password_pam_cracklib_maxrepeatZlo4Ro.xml-results
Definition oval:scap-security-guide.testing:def:138: false
Evaluation done.
[root@ssg-rhel6-devbox checks]# cd -
/var/www/html/gh/scap-security-guide/RHEL/6/input/fixes/bash
[root@ssg-rhel6-devbox bash]# bash accounts_password_pam_cracklib_maxrepeat.sh
[root@ssg-rhel6-devbox bash]# cd -
/var/www/html/gh/scap-security-guide/RHEL/6/input/checks
[root@ssg-rhel6-devbox checks]# ./testcheck.py accounts_password_pam_cracklib_maxrepeat.xml
external_variable with id : var_password_pam_cracklib_maxrepeat
Evaluating with OVAL tempfile : /tmp/accounts_password_pam_cracklib_maxrepeatRd9i_g.xml
Writing results to : /tmp/accounts_password_pam_cracklib_maxrepeatRd9i_g.xml-results
Definition oval:scap-security-guide.testing:def:138: true
Evaluation done.
new remediation - accounts_password_pam_cracklib_ucredit.sh
new remediation - accounts_password_pam_cracklib_ocredit
new remediation - accounts_password_pam_cracklib_difok.sh
new remediation - accounts_password_pam_cracklib_lcredit.sh
[bugfix] fixing typo in PAM section
accounts_password_reuse_limit.xml -> input/checks/accounts_password_pam_unix_remember.xml

- XCCDF/OVAL naming update
- Created remediation script
[Enhancement] Add OVAL for SNMP checks

- Add OVAL for SNMP checks
- Enables for RHEL 6 & 7 and Fedora
Merge remote branch 'origin/master' into add_GDM_login_banner_text
Merge pull request #28 from redhatrises/add_GDM_login_banner_text

[Enhancement] Add OVAL check for GDM login banner
Merge pull request #27 from shawndwells/pam_fixes

PAM XCCDF, OVAL, and remediation fixes
Merge pull request #34 from redhatrises/add_SNMP_oval

[Enhancement] Add OVAL for SNMP checks
Merged master fixed conflict