ic-proxy: enable in release builds

The Greenplumn release builds are configured without any extra configure
flags, it only use the ones specified in gpAux/Makefile, so we have to
enable ic-proxy in this file to include the ic-proxy feature in relase
builds.
Reviewed-by: NShaoqi Bai <bshaoqi@vmware.com>

gpAux/Makefile

@@ -126,11 +126,11 @@ APR_CONFIG=--with-apr-config=$(BLD_THIRDPARTY_BIN_DIR)/apr-1-config
 endif
 
 aix7_ppc_64_CONFIGFLAGS=--disable-gpcloud --without-readline --without-libcurl --disable-orca --disable-pxf --without-zstd $(APR_CONFIG)
-rhel6_x86_64_CONFIGFLAGS=--with-quicklz --with-gssapi --enable-mapreduce --enable-orafce ${ORCA_CONFIG} --with-libxml
-rhel7_x86_64_CONFIGFLAGS=--with-quicklz --with-gssapi --enable-mapreduce --enable-orafce ${ORCA_CONFIG} --with-libxml
+rhel6_x86_64_CONFIGFLAGS=--with-quicklz --with-gssapi --enable-mapreduce --enable-orafce --enable-ic-proxy ${ORCA_CONFIG} --with-libxml
+rhel7_x86_64_CONFIGFLAGS=--with-quicklz --with-gssapi --enable-mapreduce --enable-orafce --enable-ic-proxy ${ORCA_CONFIG} --with-libxml
 linux_x86_64_CONFIGFLAGS=${ORCA_CONFIG} --with-libxml $(APR_CONFIG)
-ubuntu18.04_x86_64_CONFIGFLAGS=--with-quicklz --with-gssapi --enable-mapreduce --enable-orafce ${ORCA_CONFIG} --with-libxml
-sles12_x86_64_CONFIGFLAGS=--with-quicklz --with-gssapi --enable-mapreduce --enable-orafce ${ORCA_CONFIG} --with-libxml
+ubuntu18.04_x86_64_CONFIGFLAGS=--with-quicklz --with-gssapi --enable-mapreduce --enable-orafce --enable-ic-proxy ${ORCA_CONFIG} --with-libxml
+sles12_x86_64_CONFIGFLAGS=--with-quicklz --with-gssapi --enable-mapreduce --enable-orafce --enable-ic-proxy ${ORCA_CONFIG} --with-libxml
 BLD_CONFIGFLAGS=$($(BLD_ARCH)_CONFIGFLAGS)
 
 CONFIGFLAGS=$(strip $(BLD_CONFIGFLAGS) --with-pgport=$(DEFPORT) $(BLD_DEPLOYMENT_SETTING))