account: don't set "Unknown" as profile name

"Unknown" is a placeholder to use at
presentation time, not as the actual profile
name that will be transmitted and saved.

This patch prevents setting a "default name"
in a vcard since the vcard can be used
without a name. If no name is available,
no name is set.

In the account list, the account alias is
showed if the profile name is not set.

Change-Id: I48cef23edc139c269fe54cd5ca8cd6de91ea6752
diff --git a/ring-android/app/src/main/res/values/strings.xml b/ring-android/app/src/main/res/values/strings.xml
index 50bcee0..23f88fa 100644
--- a/ring-android/app/src/main/res/values/strings.xml
+++ b/ring-android/app/src/main/res/values/strings.xml
@@ -175,10 +175,10 @@
 
     <!-- MenuHeaderView -->
     <string name="profile">My profile</string>
-    <string name="profile_message_warning">This is shared with your contacts</string>
+    <string name="profile_message_warning">Your profile is only shared with your contacts</string>
     <string name="open_the_gallery">Open the gallery</string>
     <string name="take_a_photo">Take a photo</string>
-    <string name="unknowm_if_empty">Unknown if empty</string>
+    <string name="profile_name_hint">Enter your name (optional)</string>
     <string name="unknown">Unknown</string>
 
     <!-- Share fragment -->