Debian init scripts: Use -a not "&&". Thanks to jcassee. Closes #84.

contrib/debian/init.d/celerybeat

@@ -93,7 +93,7 @@ if [ ! -z "$VIRTUALENV" ]; then
     fi
 fi
 
-if [ -f "$CELERYBEAT" && ! -x "$CELERYBEAT" ]; then
+if [ -f "$CELERYBEAT" -a ! -x "$CELERYBEAT" ]; then
     echo "ERROR: $CELERYBEAT is not executable."
     echo "Please make it executable by doing: chmod +x '$CELERYBEAT'"
 

contrib/debian/init.d/celeryd

@@ -89,7 +89,7 @@ if [ ! -z "$VIRTUALENV" ]; then
 fi
 
 
-if [ -f "$CELERYD" && ! -x "$CELERYD" ]; then
+if [ -f "$CELERYD" -a ! -x "$CELERYD" ]; then
     echo "ERROR: $CELERYD is not executable."
     echo "Please make it executable by doing: chmod +x '$CELERYD'"