Remove groups v2 capability

* wip removing groups v2 capabilities

* comments

* finish removing groups v2 references

* hardcode gv1migration flag on user capability, remove other references

service/src/main/java/org/whispersystems/textsecuregcm/entities/UserCapabilities.java

@@ -12,8 +12,7 @@ public class UserCapabilities {
 
   public static UserCapabilities createForAccount(Account account) {
     return new UserCapabilities(
-        account.isGroupsV2Supported(),
-        account.isGv1MigrationSupported(),
+        true,
         account.isSenderKeySupported(),
         account.isAnnouncementGroupSupported(),
         account.isChangeNumberSupported(),
@@ -21,9 +20,6 @@ public class UserCapabilities {
         account.isGiftBadgesSupported());
   }
 
-  @JsonProperty
-  private boolean gv2;
-
   @JsonProperty("gv1-migration")
   private boolean gv1Migration;
 
@@ -45,7 +41,7 @@ public class UserCapabilities {
   public UserCapabilities() {
   }
 
-  public UserCapabilities(final boolean gv2,
+  public UserCapabilities(
       boolean gv1Migration,
       final boolean senderKey,
       final boolean announcementGroup,
@@ -53,7 +49,6 @@ public class UserCapabilities {
       final boolean stories,
       final boolean giftBadges) {
 
-    this.gv2 = gv2;
     this.gv1Migration = gv1Migration;
     this.senderKey = senderKey;
     this.announcementGroup = announcementGroup;
@@ -62,10 +57,6 @@ public class UserCapabilities {
     this.giftBadges = giftBadges;
   }
 
-  public boolean isGv2() {
-    return gv2;
-  }
-
   public boolean isGv1Migration() {
     return gv1Migration;
   }