formatted maven completion and used helper function

completion/available/maven.completion.bash

@@ -1,8 +1,10 @@
 #!/usr/bin/env bash
 # Bash Maven completion
 
-_mvn()
-{
+if _command_exists mnv
+then
+    function __maven_completions()
+    {
         local cmds cur colonprefixes
         cmds="clean validate compile test package integration-test   \
         verify install deploy test-compile site generate-sources  \
@@ -32,5 +34,8 @@ _mvn()
         done
 
         return 0
-} &&
-complete -F _mvn mvn
+    }
+
+
+    complete -F __maven_completions mvn
+fi