Fix race condition in CrashGroup::find_or_create by using constraint and upsert (for pg > 9.5) or table lock
<tr>
%= t td => 'Start Time'
%= t td => $client_info->{StartupTime}
</tr>
<tr>
%= t td => 'Crash Time'
%= t td => $client_info->{CrashTime}
</tr>
<tr>
%= t td => 'Product'
%= t td => $client_info->{ProductName}
</tr>
<tr>
%= t td => 'Distributor'
%= t td => $client_info->{Distributor}
</tr>
<tr>
%= t td => 'Version'
%= t td => $client_info->{Version}
</tr>
<tr>
%= t td => 'BuildID'
%= t td => $client_info->{BuildID}
</tr>
<tr>
%= t td => 'Release Channel'
%= t td => $client_info->{ReleaseChannel} || ""
</tr>
<tr>
%= t td => 'UUID'
%= t td => $self->param('uuid');
</tr>
<tr>
%= t td => 'User ID'
%= t td => $client_info->{UserID};
</tr>