revert onlyif to unless

manifests/install.pp

@@ -19,7 +19,7 @@ class anaconda::install {
   }
 
   exec { 'ensurecondainpath':
-    onlyif   => 'echo $PATH | grep -c /miniconda/bin',
+    unless   => 'echo $PATH | grep -q /miniconda/bin',
     command  => 'export PATH="/miniconda/bin:$PATH"',
     path     => ['/bin'],
     provider => 'shell',