MissingCredentialsException: Fix grammar in javadoc

Change-Id: I6ec575a9e726d29af9c97c2b1d47e465d9c7402b

gerrit-server/src/main/java/com/google/gerrit/server/auth/MissingCredentialsException.java

diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/auth/MissingCredentialsException.java b/gerrit-server/src/main/java/com/google/gerrit/server/auth/MissingCredentialsException.java
index f853370..d30f6da 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/auth/MissingCredentialsException.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/auth/MissingCredentialsException.java
@@ -17,7 +17,7 @@
 /**
  * An authentication exception that is thrown when the credentials are not present. This indicates
  * that the AuthBackend has none of the needed information in the request to perform authentication.
- * If parts of the authentication information is available to the backend, then a different
+ * If parts of the authentication information are available to the backend, then a different
  * AuthException should be used.
  */
 public class MissingCredentialsException extends AuthException {