scripts/build-unit-test-docker: Add libcryptsetup

Upcoming changes to the estoraged repo will start using libcryptsetup to
manage an encrypted storage device.

Signed-off-by: John Wedig <johnwedig@google.com>
Change-Id: I88ca8dd8d55bd103f49b932d9fcc28e532cd2126
diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index 5171a2a..dd0eeb5 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -798,7 +798,8 @@
     libmimetic-dev \
     libxml2-utils \
     libxml-simple-perl \
-    rsync
+    rsync \
+    libcryptsetup-dev
 
 RUN npm install -g eslint@latest eslint-plugin-json@latest