Minor fix in workaround to fix installation issue with OSM IM from git repo

Change-Id: Ib157696e713660335099287cd876ac55758c20fb
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/installers/10-install-client-tools.sh b/installers/10-install-client-tools.sh
index aff534d..51153d1 100755
--- a/installers/10-install-client-tools.sh
+++ b/installers/10-install-client-tools.sh
@@ -143,8 +143,7 @@
 #python3 -m pip install --user "git+https://osm.etsi.org/gerrit/osm/IM.git@${OSM_IM_VERSION}#egg=osm-im" --upgrade
 TMP_DIR=$(mktemp -d)
 git clone https://osm.etsi.org/gerrit/osm/IM.git "$TMP_DIR/IM"
-git -C "$TMP_DIR/IM" checkout "${OSM_IM_VERSION}"
-git -C "$TMP_DIR/IM" pull "https://osm.etsi.org/gerrit/osm/IM" refs/changes/15/15515/1
+git -C "$TMP_DIR/IM" fetch "https://osm.etsi.org/gerrit/osm/IM" refs/changes/15/15515/1 && git -C "$TMP_DIR/IM" checkout FETCH_HEAD
 python3 -m pip install --user "$TMP_DIR/IM"
 python3 -m pip install --user -r "https://osm.etsi.org/gitweb/?p=osm/osmclient.git;a=blob_plain;f=requirements.txt;hb=${OSM_CLIENT_VERSION}"
 python3 -m pip install --user git+https://osm.etsi.org/gerrit/osm/osmclient.git@${OSM_CLIENT_VERSION}#egg=osmclient