meta-secure-core: fix wrong operator combination

Operations like XXX:append += "YYY" are almost always wrong and this
is a common mistake made in the metadata. Improve them to use the
standard format.

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>

meta-integrity/conf/layer.conf

@@ -24,7 +24,7 @@ LAYERRECOMMENDS_integrity = "\
     tpm \
 "
 
-BB_HASHBASE_WHITELIST:append += "\
+BB_HASHBASE_WHITELIST:append = " \
     RPM_FSK_PATH \
 "
 

meta-integrity/recipes-core/util-linux/util-linux-integrity.inc

@@ -1,4 +1,4 @@
-CFLAGS:remove += "-pie -fpie"
+CFLAGS:remove = "-pie -fpie"
 
 # We need -no-pie in case the default is to generate pie code.
 #

meta-integrity/recipes-devtools/rpm/rpm-integrity.inc

@@ -5,7 +5,7 @@ PACKAGECONFIG:append = " \
     "
 
 # IMA signing support is provided by RPM plugin.
-EXTRA_OECONF:remove += "\
+EXTRA_OECONF:remove = "\
     --disable-plugins \
 "
 EXTRA_OECONF:append:class-native = " --disable-inhibit-plugin --with-audit=no"