main/alpine-baselayout: unset script variable in profile

Otherwise, the variable is set in the login shell session:

	$ env -i sh -l
	$ echo $script
	/etc/profile.d/vte.sh

While at it, also always quote the script variable.
8 jobs for !22678 with profile-unset-scripts in 1 minute and 27 seconds (queued for 2 seconds)
latest detached
Status Job ID Name Coverage
  Lint
passed #425315
docker-alpine x86_64
lint

00:00:18

 
  Build
passed #425320
docker-alpine ci-build aarch64
build-aarch64

00:00:44

passed #425322
docker-alpine ci-build armhf
build-armhf

00:00:40

passed #425321
docker-alpine ci-build armv7
build-armv7

00:00:41

passed #425319
docker-alpine ci-build ppc64le
build-ppc64le

00:00:54

passed #425318
docker-alpine ci-build s390x
build-s390x

00:00:36

passed #425317
docker-alpine ci-build x86
build-x86

00:00:20

passed #425316
docker-alpine ci-build x86_64
build-x86_64

00:00:20