Fix skip athena and skip raspbian flags (#1735)

shared/plugins/setupBuild.gradle

@@ -11,7 +11,6 @@ ext {
 apply from: "${rootDir}/shared/nilibraries.gradle"
 
 if (!project.hasProperty('onlylinuxathena')) {
-    ext.skipAthena = true
     apply from: "${rootDir}/shared/config.gradle"
 
     model {

simulation/frc_gazebo_plugins/build.gradle

@@ -4,8 +4,8 @@ apply plugin: 'edu.wpi.first.NativeUtils'
 apply plugin: 'cpp'
 apply plugin: "google-test"
 
-ext.skipAthena = true
-ext.skipRaspbian = true
+ext.skiplinuxathena = true
+ext.skiplinuxraspbian = true
 
 apply from: "${rootDir}/shared/config.gradle"
 

simulation/gz_msgs/build.gradle

@@ -8,8 +8,8 @@ plugins {
 description = "A C++ and Java library to pass FRC Simulation Messages in and out of Gazebo."
 
 /* The simulation does not run on real hardware; so we always skip Athena */
-ext.skipAthena = true
-ext.skipRaspbian = true
+ext.skiplinuxathena = true
+ext.skiplinuxraspbian = true
 apply from: "${rootDir}/shared/config.gradle"
 
 /* Use a sort of poor man's autoconf to find the protobuf development

simulation/halsim_gazebo/build.gradle

@@ -3,8 +3,8 @@ description = "A shared object library that will interface between a robot and t
 apply plugin: 'edu.wpi.first.NativeUtils'
 apply plugin: 'cpp'
 
-ext.skipAthena = true
-ext.skipRaspbian = true
+ext.skiplinuxathena = true
+ext.skiplinuxraspbian = true
 ext.pluginName = 'halsim_gazebo'
 
 /* If gz_msgs or gazebo is not available, do not attempt a build */