[NVIDIA-IMEX] Correcting kitchen test

Author: Himani Anil Deshpande

cookbooks/aws-parallelcluster-platform/test/controls/nvidia_imex_spec.rb

@@ -29,7 +29,7 @@
     its('owner') { should eq 'root' }
     its('group') { should eq 'root' }
     its('mode') { should cmp '0755' }
-    its('content') { should match %r{/IMEX_NODE_CONFIG_FILE=#{nvidia_imex_dir}/nodes_config.cfg/} }
+    its('content') { should match %r{IMEX_NODE_CONFIG_FILE=#{nvidia_imex_dir}/nodes_config.cfg} }
   end
 
   describe file("#{nvidia_imex_dir}/nodes_config.cfg") do