Do not show "No available releases found" entries (when core bug #512218 occurs).

Sometimes along with the regular "Update available" entries in the notification email, I receive a lot of "No available releases found" entries (due to core bug #512218: Checking for available modules fails for most of the modules). Most of the times though I get an email that contains only "No available releases found" entries. In the first case these entries should be omitted from the email. In the second the email should not be sent at all (because who cares if there are no updates or no updates could be found).

Sample "No available releases found" entries received in email:

No available releases found
module_filter 7.x-2.x-dev (2013-Jan-05)
Includes: /Module filter/

No available releases found
moduleinfo 7.x-1.0+2-dev (2012-Dec-22)
Includes: /ModuleInfo/

No available releases found
path_alias_xt 7.x-1.x-dev (2011-Dec-09)
Includes: /Extended Path Aliases/

No available releases found
pathauto 7.x-1.2+9-dev (2013-Feb-06)
Includes: /Pathauto/

No available releases found
piwik 7.x-2.4+3-dev (2012-Dec-04)
Includes: /Piwik Web analytics/

No available releases found
piwik_reports 7.x-3.0-beta2+8-dev (2012-Sep-10)
Includes: /Piwik Reports/

No available releases found
profile2 7.x-1.3+0-dev (2012-Dec-26)
Includes: /Profile2, Profile2 translation/

No available releases found
profile2_regpath 7.x-2.0-beta3+0-dev (2012-Oct-24)
Includes: /Profile2 Registration Path, Profile2 Registration Path Blocks/

No available releases found
realname 7.x-1.1+0-dev (2013-Feb-26)
Includes: /Real name/

No available releases found
subpathauto 7.x-1.3+0-dev (2012-Sep-19)
Includes: /Sub-pathauto/

No available releases found
tabledragextra 7.x-1.x-dev (2012-Mar-16)
Includes: /Tabledrag Extra/

No available releases found
taxonomy_manager 7.x-1.0-rc2+0-dev (2013-Feb-20)
Includes: /Taxonomy Manager/

No available releases found
themesettings_extras 7.x-1.2+0-dev (2013-Feb-20)
Includes: /Theme settings UI extras, Theme settings vertical tabs/

No available releases found
token 7.x-1.5+0-dev (2013-Feb-24)
Includes: /Token/

No available releases found
tree 7.x-1.0-alpha1+7-dev (2013-Jan-26)
Includes: /Tree, Tree Field/

No available releases found
update_advanced 7.x-1.x-dev (2013-Mar-29)
Includes: /Update Status Advanced Settings/

No available releases found
update_detailed_email 7.x-1.x-dev (2013-Apr-02)
Includes: /Update Detailed Email/

No available releases found
variable 7.x-2.1+9-dev (2012-Dec-23)
Includes: /Variable, Variable realm, Variable store, Variable views/

No available releases found
views 7.x-3.6+4-dev (2013-Mar-29)
Includes: /Views, Views UI/

These are of no value and should not be displayed in the notification email at all.

PS: sorry for the long list. I know that a couple of example entries would suffice to explain the issue, but they wouldn't suffice to explain how annoying this is.