procps: whitelist CVE-2018-1121

This CVE is about race conditions in 'ps' which make it unsuitable for security
audits.  As these race conditions are unavoidable ps shouldn't be used for
security auditing, so this isn't a valid CVE.

(From OE-Core rev: afc529aa689daed18af29ecc64f3dae1fcbdc282)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/procps/procps_3.3.15.bb

@@ -64,3 +64,6 @@ python __anonymous() {
         d.setVarFlag('ALTERNATIVE_LINK_NAME', prog, '%s/%s' % (d.getVar('base_sbindir'), prog))
 }
 
+# 'ps' isn't suitable for use as a security tool so whitelist this CVE.
+# https://bugzilla.redhat.com/show_bug.cgi?id=1575473#c3
+CVE_CHECK_WHITELIST += "CVE-2018-1121"