Introduce iniget_sections function

This function returns list of sections from specified INI file.
It is needed for I7938f26015d953efdf720774b5ad2cee4068ac90.
'iniget_sections' is needed for automatic node enrollment to
Ironic from INI syntax file.

Change-Id: I52a69ad3bc8fc528e7f20e6b03a98f327acaaa74
Implements: blueprint ironic-ml2-integration
diff --git a/tests/test_ini_config.sh b/tests/test_ini_config.sh
index d9cb8d8..a5e1107 100755
--- a/tests/test_ini_config.sh
+++ b/tests/test_ini_config.sh
@@ -80,6 +80,11 @@
     sudo chown -R root:root ${INI_TMP_ETC_DIR}
 fi
 
+# test iniget_sections
+VAL=$(iniget_sections "${TEST_INI}")
+assert_equal "$VAL" "default aaa bbb ccc ddd eee del_separate_options \
+del_same_option del_missing_option del_missing_option_multi del_no_options"
+
 # Test with missing arguments
 BEFORE=$(cat ${TEST_INI})