Create and destroy temp PATH in tests

Since busted seems to spawn isolated child processes for every test
suite, the temporary PATH directories have to be created at the
beginning and destroyed at the end of a test suite.

spec/awful/completion_spec.lua

@@ -46,6 +46,7 @@ local function remove_test_path_dir(test_path)
 end
 
 local test_dir
+local test_path
 
 --- Get and create a temporary test dir based on `pat`, where %d gets replaced by
 -- the current PID.
@@ -65,11 +66,13 @@ describe("awful.completion.shell in empty directory", function()
         io.popen = function(...)  --luacheck: ignore
             return orig_popen(string.format('cd %s && ', test_dir) .. ...)
         end
+        test_path = get_test_path_dir()
     end)
 
     teardown(function()
         assert.True(os.remove(test_dir))
         io.popen = orig_popen  --luacheck: ignore
+        remove_test_path_dir(test_path)
     end)
 
     if has_bash then
@@ -97,12 +100,14 @@ describe("awful.completion.shell", function()
         io.popen = function(...)  --luacheck: ignore
             return orig_popen(string.format('cd %s && ', test_dir) .. ...)
         end
+        test_path = get_test_path_dir()
     end)
 
     teardown(function()
         assert.True(os.remove(test_dir .. '/localcommand'))
         assert.True(os.remove(test_dir))
         io.popen = orig_popen  --luacheck: ignore
+        remove_test_path_dir(test_path)
     end)
 
     if has_bash then
@@ -159,11 +164,14 @@ describe("awful.completion.shell handles $SHELL", function()
         gdebug.print_warning = function(message)
             print_warning_message = message
         end
+
+        test_path = get_test_path_dir()
     end)
 
     teardown(function()
         os.getenv = orig_getenv  --luacheck: ignore
         gdebug.print_warning = orig_print_warning
+        remove_test_path_dir(test_path)
     end)
 
     before_each(function()