Fix build error with -Werror=maybe-uninitialized

Signed-off-by: Peter Jones <pjones@redhat.com>
Bump version to 0.10

Development is moving so fast!

Signed-off-by: Peter Jones <pjones@redhat.com>
Fix bugs when "append" EFI vars

Few bugs are present in the "append" action:
- case ACTION_APPEND is always false because of ACTION_PRINT bit set,
- append_variable() fails if EFI var is not already present,
- add a way to specify an attribute value.

Signed-off-by: Olivier Guiter <olivier.guiter@linux.intel.com>