Modify build-dockerfile to only replace variables as set in in SOLUTIONS / MANIFEST

Signed-off-by: James Ketrenos <james.p.ketrenos@intel.com>

scripts/build-dockerfile

@@ -11,9 +11,19 @@ fi
 . SOLUTION
 . MANIFEST
 
-export $(sed -nE "s,(^[^#][^=]*).*$,\1,pg" SOLUTION | ${CMD} -d '\n')
+VARS=($(sed -nE "s,(^[^#][^=]*).*$,\1,pg" SOLUTION))
-export $(sed -nE "s,(^[^#][^=]*).*$,\1,pg" MANIFEST | ${CMD} -d '\n')
+VARS+=($(sed -nE "s,(^[^#][^=]*).*$,\1,pg" MANIFEST))
+for var in ${VARS[@]}; do
+  export ${var}
+done
 
+# Build a SHELL-FORMAT value to pass to envsubst.
+# Only those variables matched in SHELL-FORMAT will
+# be escaped by envsubst.
+ENV=''
+for var in ${VARS[@]}; do
+  ENV=${ENV}'$'${var}
+done
 
 # Remove the Dockerfile if it exists; should check
 # if it is clean first, and abort if not.
@@ -42,7 +52,7 @@ for snippet in templates/??-*.in; do
 # Template from templates/${snippet}
 #
 EOM
-  envsubst < $snippet >> Dockerfile
+  envsubst ${ENV} < $snippet >> Dockerfile
 done
 
 cat << EOM >> Dockerfile
@@ -52,7 +62,7 @@ cat << EOM >> Dockerfile
 #
 EOM
 
-envsubst < Dockerfile.solution >> Dockerfile
+envsubst ${ENV} < Dockerfile.solution >> Dockerfile
 
 cat << EOM >> Dockerfile
 
@@ -61,7 +71,7 @@ cat << EOM >> Dockerfile
 #
 EOM
 
-envsubst < templates/ending.in >> Dockerfile
+envsubst ${ENV} < templates/ending.in >> Dockerfile
 
 cat << EOM
 

templates/05-intel-proxy.in

@@ -1,6 +1,14 @@
 # Pre-install proxy configuration values
 #
 # This uses the linux-ftp.ostc.intel.com as a mirror.
+RUN { \
+  for suite in ${OS_RELEASE} ${OS_RELEASE}-updates ${OS_RELEASE}-security ${OS_RELEASE}-backports; do \
+    for component in main restricted universe multiverse; do \
+      echo "deb http://linux-ftp.ostc.intel.com/pub/mirrors/${OS_DISTRO} ${suite} ${component}" ; \
+    done \
+  done \
+} > /etc/apt/sources.list
+
 RUN { \
   echo "Acquire::http::proxy \"http://proxy-chain.intel.com:911/\";\n" ; \
   echo "Acquire::https::proxy \"http://proxy-chain.intel.com:912/\";\n" ; \