memory: Fix bad error handling in memory_region_init_ram_ptr()

memory: Fix bad error handling in memory_region_init_ram_ptr()

Commit ef701d7 screwed up handling of out-of-memory conditions.
Before the commit, we report the error and exit(1), in one place.  The
commit lifts the error handling up the call chain some, to three
places.  Fine.  Except it uses &error_abort in these places, changing
the behavior from exit(1) to abort(), and thus undoing the work of
commit 3922825 "exec: Don't abort when we can't allocate guest
memory".

The previous two commits fixed one of the three places, another one
was fixed in commit 33e0eb5.  This commit fixes the third one.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1441983105-26376-5-git-send-email-armbru@redhat.com>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>