phosphor-state-manager: use c++17

Update configure.ac to choose the c++17 standard

Change-Id: I9d96c8e5c7182c9647939621cb4ad1c971479f2d
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
diff --git a/configure.ac b/configure.ac
index f1d3a2f..bd3ecac 100644
--- a/configure.ac
+++ b/configure.ac
@@ -20,7 +20,7 @@
     AC_MSG_ERROR(["Requires phosphor-logging package."]))
 
 # Checks for typedefs, structures, and compiler characteristics.
-AX_CXX_COMPILE_STDCXX_14([noext])
+AX_CXX_COMPILE_STDCXX_17([noext])
 AX_APPEND_COMPILE_FLAGS([-Wall -Werror], [CXXFLAGS])
 
 # Checks for library functions