Add multiarch specification to apt repo config.

chrome/installer/linux/common/apt.include

 @@include@@variables.include
 
 APT_GET="`which apt-get 2> /dev/null`"
 APT_CONFIG="`which apt-config 2> /dev/null`"
 
 SOURCES_PREAMBLE="### THIS FILE IS AUTOMATICALLY CONFIGURED ###
 # You may comment out this entry, but any other modifications may be lost.\n"
 
 # Parse apt configuration and return requested variable value.
 apt_config_val() {
@@ skipping 69 matching lines @@
   # Don't do anything if the file isn't there, since that probably means the
   # user disabled it.
   if [ ! -r "$SOURCELIST" ]; then
     return 0
   fi
 
   # Basic check for active configurations (non-blank, non-comment lines).
   ACTIVECONFIGS=$(grep -v "^[[:space:]]*\(#.*\)\?$" "$SOURCELIST" 2>/dev/null)
 
   # Check if the correct repository configuration is in there.
-  REPOMATCH=$(grep -E "^[[:space:]#]*\b($REPOCONFIG|$SSLREPOCONFIG)\b" "$SOURCELIST" \
+  REPOMATCH=$(grep -E "^[[:space:]#]*\b$REPOCONFIGREGEX\b" "$SOURCELIST" \
     2>/dev/null)
 
   # Check if the correct repository is disabled.
   MATCH_DISABLED=$(echo "$REPOMATCH" | grep "^[[:space:]]*#" 2>/dev/null)
 
   # Now figure out if we need to fix things.
   BADCONFIG=1
   if [ "$REPOMATCH" ]; then
     # If it's there and active, that's ideal, so nothing to do.
     if [ ! "$MATCH_DISABLED" ]; then
@@ skipping 66 matching lines @@
 # Detect if the repo config was disabled by distro upgrade and enable if
 # necessary.
 handle_distro_upgrade() {
   if [ ! "$REPOCONFIG" ]; then
     return 0
   fi
 
   find_apt_sources
   SOURCELIST="$APT_SOURCESDIR/@@PACKAGE@@.list"
   if [ -r "$SOURCELIST" ]; then
-    REPOLINE=$(grep -E "^[[:space:]]*#[[:space:]]*($REPOCONFIG|$SSLREPOCONFIG)[[:space:]]*# disabled on upgrade to .*" "$SOURCELIST")
+    REPOLINE=$(grep -E "^[[:space:]]*#[[:space:]]*$REPOCONFIGREGEX[[:space:]]*# disabled on upgrade to .*" "$SOURCELIST")
     if [ $? -eq 0 ]; then
-      sed -i -e "s,^[[:space:]]*#[[:space:]]*\($REPOCONFIG\|$SSLREPOCONFIG\)[[:space:]]*# disabled on upgrade to .*,\1," \
+      sed -i -e "s,^[[:space:]]*#[[:space:]]*\(.*\)[[:space:]]*# disabled on upgrade to .*,\1," \
         "$SOURCELIST"
       LOGGER=$(which logger 2> /dev/null)
       if [ "$LOGGER" ]; then
         "$LOGGER" -t "$0" "Reverted repository modification: $REPOLINE."
       fi
     fi
   fi
 }
 
 DEFAULT_ARCH="@@ARCHITECTURE@@"
 
 get_lib_dir() {
   if [ "$DEFAULT_ARCH" = "i386" ]; then
     LIBDIR=lib/i386-linux-gnu
   elif [ "$DEFAULT_ARCH" = "amd64" ]; then
     LIBDIR=lib/x86_64-linux-gnu
   else
     echo Unknown CPU Architecture: "$DEFAULT_ARCH"
     exit 1
   fi
 }