iniset: fix handling of keys with spaces

Ceph for example uses them. Creation already worked, but not
updates of existing keys.

Closes-Bug: 1774956

Change-Id: I20cb61c08079b9cd9ad56ac875525abf1442bff6
diff --git a/inc/ini-config b/inc/ini-config
index 68d48d1..6fe7788 100644
--- a/inc/ini-config
+++ b/inc/ini-config
@@ -200,7 +200,7 @@
         local sep
         sep=$(echo -ne "\x01")
         # Replace it
-        $sudo sed -i -e '/^\['${section}'\]/,/^\[.*\]/ s'${sep}'^\('${option}'[ \t]*=[ \t]*\).*$'${sep}'\1'"${value}"${sep} "$file"
+        $sudo sed -i -e '/^\['${section}'\]/,/^\[.*\]/ s'${sep}'^\('"${option}"'[ \t]*=[ \t]*\).*$'${sep}'\1'"${value}"${sep} "$file"
     fi
     $xtrace
 }