Make that contact field does not contain strange characters that break the service

src/main/java/org/torproject/metrics/onionoo/docs/DetailsDocument.java

@@ -423,6 +423,9 @@ public class DetailsDocument extends Document {
   private String contact;
 
   public void setContact(String contact) {
+    if ((contact != null) && (contact.indexOf('%') != -1)) {
+      contact = contact.replace("%", "%%");
+    }
     this.contact = escapeJson(contact);
   }
 

src/main/java/org/torproject/metrics/onionoo/docs/DetailsStatus.java

@@ -128,6 +128,9 @@ public class DetailsStatus extends Document {
   private String contact;
 
   public void setContact(String contact) {
+    if ((contact != null) && (contact.indexOf('%') != -1)) {
+      contact = contact.replace("%", "%%");
+    }
     this.contact = escapeJson(contact);
   }
 

src/main/java/org/torproject/metrics/onionoo/server/ResponseBuilder.java

@@ -180,9 +180,6 @@ public class ResponseBuilder {
   }
 
   private void write(PrintWriter pw, String format, Object ... args) {
-    if (format.indexOf('%') != -1) {
-      format = format.replace("%", "%%");
-    }
     String stringToWrite = String.format(format, args);
     this.charsWritten += stringToWrite.length();
     pw.write(stringToWrite);