generate-files: make version argument mandatory

This ensures we don't accidentally build for the default version, which 
is already old.

Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com>

generate-files.sh

@@ -2,23 +2,18 @@
 
 set -e
 
-VERSION="v2021"
-
-if [ $# -gt 1 ]; then
-  echo "Usage: $0 [APERTIS_VERSION]" >&2
+if [ $# -ne 1 ]; then
+  echo "Usage: $0 APERTIS_VERSION" >&2
   exit 1
 fi
 
-if [ "$1" ]; then
-  versioncheck=$(echo $1 | grep -o 'v[0-9]\{4\}\(dev[0-9]\|pre\)\?')
-  if [ "$versioncheck" = "$1" ]; then
-    VERSION=$1
-  else
-    echo "Error: wrong Apertis version format: should be 'vXXXX[devY|pre]' with" >&2
-    echo "\tXXXX\tthe release year" >&2
-    echo "\tY\ta single digit between 0 and 3" >&2
-    exit 2
-  fi
+VERSION=$1
+versioncheck=$(echo $VERSION | grep -o 'v[0-9]\{4\}\(dev[0-9]\|pre\)\?')
+if [ "$versioncheck" != "$VERSION" ]; then
+  echo "Error: wrong Apertis version format: should be 'vXXXX[devY|pre]' with" >&2
+  echo "\tXXXX\tthe release year" >&2
+  echo "\tY\ta single digit between 0 and 3" >&2
+  exit 2
 fi
 
 projectdir=$(dirname $0)