Do not pre-set 'Build-Using to "bazel"' in pkg_deb.

Fixes: [#1037](https://github.com/bazelbuild/bazel/issues/1037)

Closes #7921.

PiperOrigin-RevId: 242123848

tools/build_defs/pkg/BUILD

diff --git a/tools/build_defs/pkg/BUILD b/tools/build_defs/pkg/BUILD
index 238cb89..bb2cd9f 100644
--- a/tools/build_defs/pkg/BUILD
+++ b/tools/build_defs/pkg/BUILD
@@ -205,6 +205,7 @@
 
 pkg_deb(
     name = "test-deb",
+    built_using = "some_test_data (0.1.2)",
     conffiles = [
         "/etc/nsswitch.conf",
         "/etc/other",

tools/build_defs/pkg/README.md

diff --git a/tools/build_defs/pkg/README.md b/tools/build_defs/pkg/README.md
index 5a2322b..d487e3e 100644
--- a/tools/build_defs/pkg/README.md
+++ b/tools/build_defs/pkg/README.md
@@ -50,7 +50,7 @@
 pkg_deb(
     name = "bazel-debian",
     architecture = "amd64",
-    built_using = "bazel (0.1.1)",
+    built_using = "unzip (6.0.1)",
     data = ":debian-data",
     depends = [
         "zlib1g-dev",
@@ -432,7 +432,7 @@
     <tr>
       <td><code>built_using</code>, <code>built_using_file</code></td>
       <td>
-        <code>String or File, default to 'Bazel'</code>
+        <code>String or File</code>
         <p>
           The tool that were used to build this package provided either inline
           (with <code>built_using</code>) or from a file (with <code>built_using_file</code>).

tools/build_defs/pkg/build_test.sh

diff --git a/tools/build_defs/pkg/build_test.sh b/tools/build_defs/pkg/build_test.sh
index 4857177..f07b729 100755
--- a/tools/build_defs/pkg/build_test.sh
+++ b/tools/build_defs/pkg/build_test.sh
@@ -186,6 +186,7 @@
   expect_log "Package: titi"
   expect_log "soméone@somewhere.com"
   expect_log "Depends: dep1, dep2"
+  expect_log "Built-Using: some_test_data"
 
   get_changes titi_test_all.changes >$TEST_log
   expect_log "Urgency: low"

tools/build_defs/pkg/make_deb.py

diff --git a/tools/build_defs/pkg/make_deb.py b/tools/build_defs/pkg/make_deb.py
index d09781e..4705675 100644
--- a/tools/build_defs/pkg/make_deb.py
+++ b/tools/build_defs/pkg/make_deb.py
@@ -43,7 +43,7 @@
     ('Maintainer', True, False),
     ('Description', True, True),
     ('Homepage', False, False),
-    ('Built-Using', False, False, 'Bazel'),
+    ('Built-Using', False, False, None),
     ('Distribution', False, False, 'unstable'),
     ('Urgency', False, False, 'medium'),
 ]