Replace "==" with "=" in shell script test

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

cfg.mk

@@ -22,7 +22,6 @@ local-checks-to-skip = \
     sc_bindtextdomain	 \
     sc_prohibit_empty_lines_at_EOF \
     sc_prohibit_path_max_allocation \
-    sc_prohibit_test_double_equal \
     sc_trailing_blank \
 
 #SHELL=bash -x

tests/test-help.sh

@@ -31,7 +31,7 @@ test_recursive() {
     echo "$cmd" 1>&2
     $cmd --help 1>out 2>err
     # --help message goes to standard output
-    if [ "$root" == "1" ] ; then
+    if [ "$root" = "1" ] ; then
         assert_file_has_content out "[Uu]sage"
         assert_file_has_content out "$cmd"
     fi