network_manager: Refactor config rewriting

This re-arranges the code to disconnect config resetting from default
config file writing.

Change-Id: I7106da19fab29982f2efd3cd9871bcd651fb7216
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/network_manager.hpp b/src/network_manager.hpp
index 7ca9939..47a1e4d 100644
--- a/src/network_manager.hpp
+++ b/src/network_manager.hpp
@@ -102,13 +102,9 @@
     }
 
     /** @brief create the default network files for each interface
-     *  @detail if force param is true then forcefully create the network
-     *          files otherwise if network file doesn't exist then
-     *          create it.
-     *  @param[in] force - forcefully create the file
      *  @return true if network file created else false
      */
-    bool createDefaultNetworkFiles(bool force);
+    bool createDefaultNetworkFiles();
 
     /** @brief This function gets the MAC address from the VPD and
      *  sets it on the corresponding ethernet interface during first