stdlib: Add get_local_path() call to Looppoint resources

Due to a change introduced in https://github.com/gem5/gem5/pull/625, a
gem5 resource will not download any external files until
`get_local_path()` is called. In the construction of the Looppoint
Resources this function was not called, the `local_path` variable was
called directly. As such, an error occured.

The downside of this fix is the Looppoint resources external files are
downloaded when `obtain_resource` is called, thus the bandwidth savings
introduced with https://github.com/gem5/gem5/pull/625 will not occur for
Looppoint resources. However, https://github.com/gem5/gem5/issues/644
proposes a fix which would supercede the
https://github.com/gem5/gem5/pull/625 solution.

Change-Id: I52181382a03e492ec1cb58b01e71bc4820af9ccc

src/python/gem5/resources/resource.py

@@ -578,7 +578,9 @@ class LooppointCsvResource(FileResource, LooppointCsvLoader):
             resource_version=resource_version,
             downloader=downloader,
         )
-        LooppointCsvLoader.__init__(self, pinpoints_file=Path(local_path))
+        LooppointCsvLoader.__init__(
+            self, pinpoints_file=Path(self.get_local_path())
+        )
 
     def get_category_name(cls) -> str:
         return "LooppointCsvResource"
@@ -606,7 +608,7 @@ class LooppointJsonResource(FileResource, LooppointJsonLoader):
             downloader=downloader,
         )
         LooppointJsonLoader.__init__(
-            self, looppoint_file=local_path, region_id=region_id
+            self, looppoint_file=self.get_local_path(), region_id=region_id
         )
 
     def get_category_name(cls) -> str: