support/scripts/generate-gitlab-ci-yml: improve test-pkg support

Following the example of test-pkg config described in commit
"12c7a05da1 utils/test-pkg: add gitlab-ci support" to test a defconfig
fragment that contains a disabled option is currently possible, but
it do requires one to change the git config core.commentChart so the
lines starting with "#" are not discarded by git when creating/editing
the commit message.

For instance, without the indentation the 3rd line below would be
excluded from the commit message when the editor is closed:
    test-pkg config:
    SOME_OPTION=y
    # OTHER_OPTION is not set
    SOME_VARIABLE="some value"

Requiring to change git configs is not very nice.
So make the developer's life easier by changing the sed expression to
remove indentation with spaces from a defconfig fragment found on a
commit message.
For instance these lines become valid and generate a defconfig fragment
without the indentation of one space to be tested in GitLab CI:
test-pkg config:
 SOME_OPTION=y
 # OTHER_OPTION is not set
 SOME_VARIABLE="some value"

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 0ad3ae14c5)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

support/scripts/generate-gitlab-ci-yml

@@ -91,7 +91,7 @@ gen_tests() {
 
     # Retrieve defconfig for test-pkg from the git commit message (if any)
     if grep -q -E '^test-pkg config:$' <<<"${CI_COMMIT_DESCRIPTION}"; then
-        sed -r -n -e '/^test-pkg config:$/{:a;n;p;ba;}' \
+        sed -r -n -e '/^test-pkg config:$/{:a;n;s/^ +//;p;ba;}' \
             <<<"${CI_COMMIT_DESCRIPTION}" \
             >defconfig.frag
         if [ ! -s defconfig.frag ]; then