x509_crt_parse() did not increase total_failed on PEM error

Result was that PEM errors in files with multiple certificates were not
detectable by the user.

library/x509_crt.c

@@ -898,6 +898,7 @@ int x509_crt_parse( x509_crt *chain, const unsigned char *buf, size_t buflen )
                 if( first_error == 0 )
                     first_error = ret;
 
+                total_failed++;
                 continue;
             }
             else