install_pip: don't fail when not installed

On some platforms, "python -m pip" isn't available.  Currently this is
run undconditionally from the "get_versions" function; remove the call.

Change-Id: I91d6c66d055f02fa7b4368593b629933f82d8117
diff --git a/tools/install_pip.sh b/tools/install_pip.sh
index 0082e9f..eb0f6eb 100755
--- a/tools/install_pip.sh
+++ b/tools/install_pip.sh
@@ -46,15 +46,13 @@
 function get_versions {
     # FIXME(dhellmann): Deal with multiple python versions here? This
     # is just used for reporting, so maybe not?
-    PIP=$(which pip 2>/dev/null || which pip-python 2>/dev/null || true)
+    PIP=$(which pip 2>/dev/null || which pip-python 2>/dev/null || which pip3 2>/dev/null || true)
     if [[ -n $PIP ]]; then
         PIP_VERSION=$($PIP --version | awk '{ print $2}')
         echo "pip: $PIP_VERSION"
     else
         echo "pip: Not Installed"
     fi
-    # Show python3 module version
-    python${PYTHON3_VERSION} -m pip --version
 }