drush.ini lines with periods in key names are ignored

We had a hard time overriding php.ini settings with periods in them (e.g. xdebug.remote_enable = On). We had to change the sed a bit. Assigning to Greg for review and commit.

--- /usr/local/bin/drush5    2012-11-12 20:54:46.000000000 +0000
+++ /usr/local/bin/drushnbc    2013-01-04 16:17:43.000000000 +0000
@@ -80,7 +80,7 @@
   php_options="--php-ini $drush_php_ini"
 fi
 if [ "x$drush_php_override" != "x" ] ; then
-  php_options=`grep '^[a-z_A-Z0-9]\+ *=' $drush_php_override | sed -e 's|\([^ =]*\) *= *\(.*\)|\1="\2"|' -e 's| ||g' -e 's|^|-d |' | tr '\n\r' '  '`
+  php_options=`grep '^[a-z_A-Z0-9.]\+ *=' $drush_php_override | sed -e 's|\([^ =]*\) *= *\(.*\)|\1="\2"|' -e 's| ||g' -e 's|^|-d |' | tr '\n\r' '  '`
 fi
 
 # Pass in the path to php so that drush knows which one