Rename keystore.{h|cpp} to KeyStore.{h|cpp}

We currently have two different keystore.h files.  This renames one of
them, and the corresponding implementation, to KeyStore.h, which
tracks the class name.

Test: runtest --path cts/tests/tests/keystore/src/android/keystore/cts
Change-Id: I910e3d60d165b65d055e7da92acd04d3ee73a6d3
diff --git a/keystore/Android.bp b/keystore/Android.bp
index b58671c..ef8bc72 100644
--- a/keystore/Android.bp
+++ b/keystore/Android.bp
@@ -21,6 +21,7 @@
 
     srcs: [
         ":IKeyAttestationApplicationIdProvider.aidl",
+        "KeyStore.cpp",
         "auth_token_table.cpp",
         "blob.cpp",
         "entropy.cpp",
@@ -28,7 +29,6 @@
         "key_store_service.cpp",
         "keyblob_utils.cpp",
         "keymaster_enforcement.cpp",
-        "keystore.cpp",
         "keystore_attestation_id.cpp",
         "keystore_main.cpp",
         "keystore_utils.cpp",