keystore: Fix PEM certs handling am: 7ad2a87249 am: 84da89dff4 am: 7f9a187432

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/wpa_supplicant_8/+/15433405

Change-Id: I33c5cde9edad3dd0c93df28e7a6e8581ba7c5c58