Fix shell function is_script_executed

It used to return error when tested inside a login shell, because $0 is
"-bash" and `basename` was trying to interpret -b as an option.

Change-Id: I5faa2dc01e50c7d5bcfc0ab1fcfd910b2538afc2
Reviewed-by: Heikki Halmet <heikki.halmet@qt.io>

coin/provisioning/common/unix/common.sourced.sh

@@ -65,8 +65,10 @@ fatal () {
     fi
 }
 
+# Takes one argument which should be the filename of this script. Returns true
+# if the script is being sourced, false if the script is being executed.
 is_script_executed () {
-   [ x"$(basename "$0")" = x"$1" ]
+    [ x"$(basename $(echo "$0" | sed s/^-//))" = x"$1" ]
 }