Fixup gradle-mvn-push script

Summary: Previously was looking at the wrong credential properties.

Reviewed By: nscoding

Differential Revision: D7647870

fbshipit-source-id: f9b8e5dbc6e999796ab55bcea217c529b7205a85

gradle/gradle-mvn-push.gradle

@@ -22,11 +22,11 @@ def isReleaseBuild() {
 }
 
 def getRepositoryUsername() {
-  return hasProperty('NEXUS_USERNAME') ? NEXUS_USERNAME : ""
+  return hasProperty('repositoryUsername') ? property('repositoryUsername') : ""
 }
 
 def getRepositoryPassword() {
-  return hasProperty('NEXUS_PASSWORD') ? NEXUS_PASSWORD : ""
+  return hasProperty('repositoryPassword') ? property('repositoryPassword') : ""
 }
 
 def configurePom(pom) {
@@ -118,4 +118,4 @@ afterEvaluate { project ->
     archives androidSourcesJar
     archives androidJavadocsJar
   }
-}
+}