Make command line variable override scope syntax consistent with buildfile

Before:

$ b dir/:foo=bar ...

After:

$ b dir/foo=bar

Alternatively (the buildfile syntax):

$ b 'dir/ foo=bar'

Note that the (rarely used) scope visibility modifier now leads to a
double slash:

$ b dir//foo=bar

1 files changed, 2 insertions, 2 deletions

diff --git a/old-tests/variable/override/test.sh b/old-tests/variable/override/test.sh
index 710cf28..76409d8 100755
--- a/old-tests/variable/override/test.sh
+++ b/old-tests/variable/override/test.sh
@@ -83,7 +83,7 @@ p/d   : X
 p/d/t : X
 EOF
 
-test ./:v=X <<EOF
+test ./v=X <<EOF
 /     :
 .     : X
 d     : X
@@ -93,7 +93,7 @@ p/d   : X
 p/d/t : X
 EOF
 
-test ./p/:v=X <<EOF
+test ./p/v=X <<EOF
 /     :
 .     :
 d     :