Make bintray parameters optional

Summary:
By declaring the properties first, before using them in the scripts, you no
longer get an exception if you fail to specify them.

You can now build artifacts or run tests without specifying your bintray
password, which is probably what you want.

Reviewed By: emilsjolander

Differential Revision: D4913103

fbshipit-source-id: 8787af8973cebb84cd59e18c63a3a9f28e0ec348

gradle.properties

@@ -0,0 +1,4 @@
+bintrayUsername=
+bintrayApiKey=
+bintrayGpgPassword=
+dryRun=false

gradle/android-jcenter-install.gradle

@@ -12,19 +12,19 @@ ext {
 }
 
 def getBintrayUsername() {
-    return hasProperty('bintrayUsername') ? property('bintrayUsername') : System.getenv('BINTRAY_USERNAME')
+    return property('bintrayUsername') || System.getenv('BINTRAY_USERNAME')
 }
 
 def getBintrayApiKey() {
-    return hasProperty('bintrayApiKey') ? property('bintrayApiKey') : System.getenv('BINTRAY_API_KEY')
+    return property('bintrayApiKey') || System.getenv('BINTRAY_API_KEY')
 }
 
 def getBintrayGpgPassword() {
-    return hasProperty('bintrayGpgPassword') ? property('bintrayGpgPassword') : System.getenv('BINTRAY_GPG_PASSWORD')
+    return property('bintrayGpgPassword') || System.getenv('BINTRAY_GPG_PASSWORD')
 }
 
 def dryRunOnly() {
-    return hasProperty('dryRun') ? property('dryRun').toBoolean() : false 
+    return hasProperty('dryRun') ? property('dryRun').toBoolean() : false
 }
 
 def pomConfig = {

java/build.gradle

@@ -1,4 +1,4 @@
-apply plugin: "com.jfrog.bintray"
+apply plugin: 'com.jfrog.bintray'
 apply plugin: 'com.android.library'
 apply plugin: 'com.github.dcendents.android-maven'
 apply plugin: 'maven-publish'