check_python_script: Make an actual script.

Signed-off-by: Tim 'mithro' Ansell <me@mith.ro>
diff --git a/.github/travis/check_python_script.sh b/.github/travis/check_python_script.sh
old mode 100644
new mode 100755
index 4695a84..ee34550
--- a/.github/travis/check_python_script.sh
+++ b/.github/travis/check_python_script.sh
@@ -8,6 +8,8 @@
 #
 # SPDX-License-Identifier:	ISC
 
+set -e
+
 echo
 echo "==================================="
 echo "Check python utf coding and shebang"
@@ -32,14 +34,14 @@
     for file in $ERROR_FILES_SHEBANG; do
         echo "ERROR: $file does not have the python3 shebang."
     done
-    return 1
+    exit 1
 fi
 
 if [ ! -z "$ERROR_FILES_UTF_CODING" ]; then
     for file in $ERROR_FILES_UTF_CODING; do
         echo "ERROR: $file does not have the utf encoding set."
     done
-    return 1
+    exit 1
 fi
 
 echo
diff --git a/.travis.yml b/.travis.yml
index 278aff6..3bfc876 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@
 install:
   - source prepareenv.sh
   - ./.github/travis/check_license.sh
-  - source .github/travis/check_python_script.sh
+  - ./.github/travis/check_python_script.sh
 
 script:
   - conda activate yosys-env