Improve error message when Modify Account capability is required

If a user without the Modify Account (or Administrator) capability
attempts to use one of the following endpoints for a user other
than 'self':

- Get edit preferences
- Set edit preferences
- Set diff preferences
- Set preferences

an AuthException is raised with the message:

  "restricted to members of Modify Accounts".

Aside from the fact that the capability name is wrong (it should not
have the trailing 's'), this message is not particulaly user friendly.

Change it to:

  "requires Modify Account capability"

Note that there is some inconsistency in required capability for the
"get" access to these preference endpoints. "Edit preferences" is the
only one that allows "get" with the "Modify Account" capability. The
"diff preferences" and the "preferences" endpoints only allow "get" for
administrators. Fixing this is not within the scope of this change.

Change-Id: Ifa3ccb6e0f43220605906bbda771334cc650972e
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/GetEditPreferences.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/GetEditPreferences.java
index d99b68f..cdc2044 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/GetEditPreferences.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/GetEditPreferences.java
@@ -54,7 +54,7 @@
       IOException, ConfigInvalidException {
     if (self.get() != rsrc.getUser()
         && !self.get().getCapabilities().canModifyAccount()) {
-      throw new AuthException("restricted to members of Modify Accounts");
+      throw new AuthException("requires Modify Account capability");
     }
 
     return readFromGit(
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/SetDiffPreferences.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/SetDiffPreferences.java
index 9617d94..d7685ac 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/SetDiffPreferences.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/SetDiffPreferences.java
@@ -63,7 +63,7 @@
       RepositoryNotFoundException, IOException, OrmException {
     if (self.get() != rsrc.getUser()
         && !self.get().getCapabilities().canModifyAccount()) {
-      throw new AuthException("restricted to members of Modify Accounts");
+      throw new AuthException("requires Modify Account capability");
     }
 
     if (in == null) {
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/SetEditPreferences.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/SetEditPreferences.java
index d51e24a..95a780e 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/SetEditPreferences.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/SetEditPreferences.java
@@ -63,7 +63,7 @@
       IOException, ConfigInvalidException {
     if (self.get() != rsrc.getUser()
         && !self.get().getCapabilities().canModifyAccount()) {
-      throw new AuthException("restricted to members of Modify Accounts");
+      throw new AuthException("requires Modify Account capability");
     }
 
     if (in == null) {
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/SetPreferences.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/SetPreferences.java
index ff4a6a8..3f1feb4 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/SetPreferences.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/SetPreferences.java
@@ -101,7 +101,7 @@
           OrmException, IOException, ConfigInvalidException {
     if (self.get() != rsrc.getUser()
         && !self.get().getCapabilities().canModifyAccount()) {
-      throw new AuthException("restricted to members of Modify Accounts");
+      throw new AuthException("requires Modify Account capability");
     }
 
     checkDownloadScheme(i.downloadScheme);