contrib: Use correct var to write repo name in git_hashes.txt

We want to write repo name in there, not $dep which actually doesn't
exist in local context of have_repo function. In most cases it's
actually the same because in almost all cases $dep is passed as $1 to
have_repo and thus is the same as local $repo. But in a few recipes
which don't use build_repo directly but instead use have_repo and build
manually, $dep may not point to $repo. That's the case for osmocom-bb
for instance. As a result, "libosmocore" is printed twice, were second
word should be "osmocom-bb".

Change-Id: I7a7db7cf4cc020295d216c60d6dc688f110916dc

contrib/jenkins-build-common.sh

@@ -92,7 +92,7 @@ have_repo() {
 
   git rev-parse HEAD
 
-  echo "$(git rev-parse HEAD) $dep" >> "$prefix_real/${name}_git_hashes.txt"
+  echo "$(git rev-parse HEAD) $repo" >> "$prefix_real/${name}_git_hashes.txt"
 
   cd "$base"
 }