Fixed shebang kernel limitation with virtualenv during test run (https://github.com/pypa/virtualenv/issues/596)

Change-Id: Iab829e487347098fee62812f7f5123b583c5888e
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 4ee4e0f..9761585 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -39,7 +39,7 @@
     log_info "Setting up Python virtualenv"
     virtualenv $VENV_DIR
     source ${VENV_DIR}/bin/activate
-    pip install salt${PIP_SALT_VERSION}
+    python -m pip install salt${PIP_SALT_VERSION}
 }
 
 setup_mock_bin() {
@@ -125,7 +125,7 @@
 
 salt_run() {
     [ -e ${VENV_DIR}/bin/activate ] && source ${VENV_DIR}/bin/activate
-    salt-call ${SALT_OPTS} $*
+    python $(which salt-call) ${SALT_OPTS} $*
 }
 
 prepare() {