PEL:log_id_test: Remove file when testcase done

A testcase was missing a delete of a temporary file it created.  Delete
it so it isn't left around.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I4666241374ee7b6e260210539e7e29b34d018600
diff --git a/test/openpower-pels/log_id_test.cpp b/test/openpower-pels/log_id_test.cpp
index 9588b07..e18bff3 100644
--- a/test/openpower-pels/log_id_test.cpp
+++ b/test/openpower-pels/log_id_test.cpp
@@ -94,4 +94,6 @@
     EXPECT_NE(generatePELID(), 0x50000003);
     EXPECT_NE(generatePELID(), 0x50000004);
     EXPECT_NE(generatePELID(), 0x50000005);
+
+    fs::remove_all(fs::path{backingFile}.parent_path());
 }