ECLAIR: Cleans mcuboot repo between builds

Cleans the mcuboot repo between builds, this is to remove the applied
patches which attempt to be applied a second time if no reset and
returns failure.

Change-Id: I003d1a579b483faa6dfc42475394714224b8d38b
Signed-off-by: Matthew Dalzell <matthew.dalzell@arm.com>
diff --git a/run-eclair-builds.sh b/run-eclair-builds.sh
index fd464b5..1b7f32c 100755
--- a/run-eclair-builds.sh
+++ b/run-eclair-builds.sh
@@ -20,6 +20,7 @@
     (cd psa-arch-tests; git checkout-index -faq; git clean -fdq)
     (cd trusted-firmware-m; git checkout-index -faq; git clean -fdq)
     (cd t_cose; git checkout-index -faq; git clean -fdq)
+    (cd mcuboot; git checkout-index -faq; git clean -fdq)
     eclair_tfm_set_toolchain_path
     detachLicense $LICENSE_LEASE
     tf-m-ci-scripts/run-build.sh