Try new md5 API endpoint

Hopefully this is more stable. It seems that too many queries to the
normal RNA endpoint cause issues. Hopefully using this end point
alleviates them.

Rfam/Lib/Bio/Rfam/Utils.pm

@@ -2939,7 +2939,7 @@ sub ncbi_taxonomy_fetch_taxinfo {
 sub rnacentral_md5_lookup {
   my ( $in_md5 ) = @_;
 
-  my $rnacentral_url = "https://rnacentral.org/api/v1/rna?md5=" . $in_md5;
+  my $rnacentral_url = "https://rnacentral.org/api/v1/md5/" . $in_md5;
   #printf("rnacentral_url: $rnacentral_url\n");
   my $json = get($rnacentral_url);
   if(! defined $json) { croak "ERROR trying to fetch from rnacentral using md5: " . $in_md5; }
@@ -2952,13 +2952,11 @@ sub rnacentral_md5_lookup {
   my $id   = undef;
   my $desc = undef;
 
-  if((defined $decoded_json->{'results'}) &&
-     (defined $decoded_json->{'results'}[0]{'md5'}) &&
-     (defined $decoded_json->{'results'}[0]{'rnacentral_id'})) {
+  if((defined $decoded_json->{'rnacentral_id'})) {
     $have_seq = 1;
-    $md5  = $decoded_json->{'results'}[0]{'md5'};
-    $id   = $decoded_json->{'results'}[0]{'rnacentral_id'};
-    $desc = $decoded_json->{'results'}[0]{'description'};
+    $md5  = $in_md5;
+    $id   = $decoded_json->{'rnacentral_id'};
+    $desc = $decoded_json->{'description'};
   }
 
   return ($have_seq, $md5, $id, $desc);