rtbCheckNativeDependencies avoid extra checks

Test/Interactive/rtbCheckNativeDependencies.m

@@ -27,24 +27,6 @@ openExr = checkSystem('OpenEXR', ...
     'It looks like the OpenEXR library is not installed.  Please visit http://www.openexr.com/.  You might also try "sudo apt-get install openexr" or similar.');
 
 
-%% Check for Docker, the preferred way to obtain renderers.
-docker = checkSystem('Docker', ...
-    'docker ps', ...
-    'It looks like Docker is not installed.  Please visit https://github.com/RenderToolbox/RenderToolbox4/wiki/Docker.');
-
-
-%% Check for a local installation of the Mitsuba renderer.
-mitsuba = checkSystem('Mitsuba', ...
-    'which mitsuba', ...
-    'It looks like Mitsuba is not installed.  Please visit https://www.mitsuba-renderer.org/.  Or, consider installing Docker so that RenderToolbox can get Mitsuba for you.');
-
-
-%% Check for a local installation of the PBRT renderer.
-pbrt = checkSystem('PBRT', ...
-    'which pbrt', ...
-    'It looks like PBRT is not installed.  Please visit https://github.com/ydnality/pbrt-v2-spectral.  Or, consider installing Docker so that RenderToolbox can get PBRT for you.');
-
-
 %% OpenEXR is required.
 if 0 ~= openExr.status
     status = openExr.status;
@@ -54,6 +36,12 @@ if 0 ~= openExr.status
 end
 
 
+%% Check for Docker, the preferred way to obtain renderers.
+docker = checkSystem('Docker', ...
+    'docker ps', ...
+    'It looks like Docker is not installed.  Please visit https://github.com/RenderToolbox/RenderToolbox4/wiki/Docker.');
+
+
 %% Docker can cover both renderers.
 if 0 == docker.status
     status = 0;
@@ -63,6 +51,18 @@ if 0 == docker.status
 end
 
 
+%% Check for a local installation of the Mitsuba renderer.
+mitsuba = checkSystem('Mitsuba', ...
+    'which mitsuba', ...
+    'It looks like Mitsuba is not installed.  Please visit https://www.mitsuba-renderer.org/.  Or, consider installing Docker so that RenderToolbox can get Mitsuba for you.');
+
+
+%% Check for a local installation of the PBRT renderer.
+pbrt = checkSystem('PBRT', ...
+    'which pbrt', ...
+    'It looks like PBRT is not installed.  Please visit https://github.com/ydnality/pbrt-v2-spectral.  Or, consider installing Docker so that RenderToolbox can get PBRT for you.');
+
+
 %% Check for both renderers.
 if 0 ~= mitsuba.status
     status = mitsuba.status;