Fix some invalid-format datetimes in queries.

Fix some hard-coded, string datetime representations in queries that
were using an invalid format that no longer works with MySQL 5.5.  These
datetime literals now use the correct MySQL SQL datetime literal format
(which is also the ISO SQL datetime literal format).

Huge thanks to Rob Smith for testing with MySQL 5.5 and seeking out the
datetime-usage within queries.

Refs #8585 (possibly fixes #8585).
(cherry picked from commit 7e33788)

mythtv/libs/libmyth/programinfo.cpp

@@ -2661,7 +2661,7 @@ void ProgramInfo::UpdateLastDelete(bool setTime) const
     }
     else
     {
-        query.prepare("UPDATE record SET last_delete = '0000-00-00T00:00:00' "
+        query.prepare("UPDATE record SET last_delete = '0000-00-00 00:00:00' "
                       "WHERE recordid = :RECORDID");
     }
     query.bindValue(":RECORDID", recordid);

mythtv/libs/libmythtv/dbcheck.cpp

@@ -2011,7 +2011,7 @@ NULL
 "UPDATE settings SET value = 'MythFillGrabberSuggestsTime' "
     "WHERE value = 'HonorGrabberNextSuggestedMythfilldatabaseRunTime';",
 "UPDATE settings SET value = 'MythFillSuggestedRunTime', "
-    "    data = '1970-01-01T00:00:00' "
+    "    data = '1970-01-01 00:00:00' "
     "WHERE value = 'NextSuggestedMythfilldatabaseRun';",
 NULL
 };

mythtv/programs/mythbackend/scheduler.cpp

@@ -1456,9 +1456,10 @@ void Scheduler::UpdateNextRecord(void)
             if (nextRecMap[recid].isNull() || !next_record.isValid())
             {
                 subquery.prepare("UPDATE record "
-                                 "SET next_record = '0000-00-00T00:00:00' "
+                                 "SET next_record = '0000-00-00 00:00:00' "
                                  "WHERE recordid = :RECORDID;");
                 subquery.bindValue(":RECORDID", recid);
+
             }
             else
             {