Add new seccomp warning text to ignore pattern.

[nuclearsandwich]

Recent versions of docker give a slightly different seccomp warning.

Before example:

08:24:05 # BEGIN SECTION: Look for warnings
08:24:05 Found 1 warnings:
08:24:05 
08:24:05 - WARNING: daemon is not using the default seccomp profile
08:24:05 
08:24:05 Marking build as unstable

After example:

08:24:50 # BEGIN SECTION: Look for warnings
08:24:50 No warnings found
08:24:50 # END SECTION