Small improvements

app/src/main/java/eu/faircode/email/ActivitySetup.java

@@ -1033,7 +1033,7 @@ public class ActivitySetup extends ActivityBase implements FragmentManager.OnBac
                             // throws DecoderException extends IllegalStateException
                             PemObject pem = new PemReader(new InputStreamReader(is)).readPemObject();
                             if (pem == null)
-                                throw new IllegalStateException();
+                                throw new IllegalStateException("Invalid key file");
                             ByteArrayInputStream bis = new ByteArrayInputStream(pem.getContent());
                             cert = (X509Certificate) fact.generateCertificate(bis);
                         }

app/src/main/java/eu/faircode/email/AdapterContact.java

@@ -135,7 +135,7 @@ public class AdapterContact extends RecyclerView.Adapter<AdapterContact.ViewHold
                      */
                     ParcelFileDescriptor pfd = context.getContentResolver().openFileDescriptor(uri, "r");
                     if (pfd == null)
-                        throw new IllegalArgumentException();
+                        throw new IllegalArgumentException("Contact inaccessible");
                     pfd.close();
 
                     ivAvatar.setImageURI(uri);