Make the name of the signature verify feature unique

The verify_signature feature name is the same as the one used
in the phosphor-software-manager repo which manages the BMC
firmware updates. Change the name to make it different to
be able to control enabling the feature individually via recipes,
since enabling it on the phosphor recipe enables it for the
pnor code as well (due to the recipe dependency on
virtual-obmc-image-manager).

Change-Id: I73e446dd6d5f0995132bc60403e08d16d07703bd
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/configure.ac b/configure.ac
index fd8a17d..385af26 100755
--- a/configure.ac
+++ b/configure.ac
@@ -97,11 +97,11 @@
 AC_DEFINE_UNQUOTED([SIGNATURE_FILE_EXT], ["$SIGNATURE_FILE_EXT"], [The extension of the Signature file])
 
 # setup signature verification
-AC_ARG_ENABLE([verify_signature],
-    AS_HELP_STRING([--enable-verify_signature], [Enable image signature validation.]))
-AS_IF([test "x$enable_verify_signature" == "xyes"], \
+AC_ARG_ENABLE([verify_pnor_signature],
+    AS_HELP_STRING([--enable-verify_pnor_signature], [Enable image signature validation.]))
+AS_IF([test "x$enable_verify_pnor_signature" == "xyes"], \
     [AC_DEFINE([WANT_SIGNATURE_VERIFY],[],[Enable image signature validation.])])
-AM_CONDITIONAL([WANT_SIGNATURE_VERIFY_BUILD], [test "x$enable_verify_signature" == "xyes"])
+AM_CONDITIONAL([WANT_SIGNATURE_VERIFY_BUILD], [test "x$enable_verify_pnor_signature" == "xyes"])
 
 AC_DEFINE(CHASSIS_STATE_PATH, "/xyz/openbmc_project/state/chassis0",
     [The chassis state path.])