security: Separate TPM locator modification and database resetting in PIB

Change-Id: I80c2805b6e1204b95d59a090a6a04e1ee62fb6e5
Refs: #3203
diff --git a/src/security/pib/pib-impl.hpp b/src/security/pib/pib-impl.hpp
index 6f233f1..9b343f5 100644
--- a/src/security/pib/pib-impl.hpp
+++ b/src/security/pib/pib-impl.hpp
@@ -60,12 +60,9 @@
 
 public: // TpmLocator management
   /**
-   * @brief Set the corresponding TPM information to @p tpmLocator.
+   * @brief Set the corresponding TPM information to @p tpmLocator
    *
-   * If the provided @p tpmLocator is different from the existing one, the
-   * content in PIB will be cleaned up, otherwise nothing will be changed.
-   *
-   * @param tpmLocator The name for the new TPM locator
+   * This method does not reset contents of the PIB
    */
   virtual void
   setTpmLocator(const std::string& tpmLocator) = 0;
@@ -108,7 +105,15 @@
   virtual void
   removeIdentity(const Name& identity) = 0;
 
-  /// @brief Get the name of all the identities
+  /**
+   * @brief Erasing all certificates, keys, and identities
+   */
+  virtual void
+  clearIdentities() = 0;
+
+  /**
+   * @brief Get the name of all the identities
+   */
   virtual std::set<Name>
   getIdentities() const = 0;