Fix to change.log

With the migration to .rst from .md, the Issues Resolved and
Known Issues sections for v1.4 were using Header 1 format.

This patch changes to using Header 2 for these sections.

Change-Id: Ic3127d84eb169a65039fd4cc8284c6429302732d
Signed-off-by: David Cunado <david.cunado@arm.com>
1 file changed