Revert "Check if the lockfile changed"

This reverts commit f2ea93a.

buildbot/master/master.cfg

@@ -183,7 +183,6 @@ linux_dev_factory = create_servo_factory([
     steps.ShellCommand(command=["./mach", "test-unit"], env=linux_headless_env),
     steps.ShellCommand(command=["./mach", "test-ref", "--kind", "cpu"], env=linux_headless_env),
     steps.Compile(command=["./mach", "build-cef"], env=linux_headless_env),
-    steps.ShellCommand(command=["[[ ! $(git diff -- */*/Cargo.lock) ]]"], env=linux_headless_env),
 ])
 
 linux_rel_factory = create_servo_factory([
@@ -198,7 +197,6 @@ linux_rel_factory = create_servo_factory([
                        env=linux_headless_env, logfiles={"test-css.log": "test-css.log"}),
     steps.ShellCommand(command=["gzip", "test-css.log"], env=linux_headless_env),
     steps.Compile(command=["./mach", "build-cef", "--release"], env=linux_headless_env),
-    steps.ShellCommand(command=["[[ ! $(git diff -- */*/Cargo.lock) ]]"], env=linux_headless_env),
 ])
 
 task_limited_test_env = dict({'RUST_TEST_TASKS': '1'}, **mac_test_env)
@@ -211,7 +209,6 @@ mac_rel_wpt_factory = create_servo_factory([
                                 "--log-raw", "test-wpt.log"],
                        env=mac_test_env, logfiles={"test-wpt.log": "test-wpt.log"}),
     steps.ShellCommand(command=["gzip", "test-wpt.log"], env=mac_test_env),
-    steps.ShellCommand(command=["[[ ! $(git diff -- */*/Cargo.lock) ]]"], env=linux_headless_env),
 ])
 
 mac_dev_ref_unit_factory = create_servo_factory([
@@ -220,7 +217,6 @@ mac_dev_ref_unit_factory = create_servo_factory([
                        env=task_limited_test_env),
     steps.ShellCommand(command=["./mach", "test-unit"], env=mac_test_env),
     steps.Compile(command=["./mach", "build-cef"], env=mac_test_env),
-    steps.ShellCommand(command=["[[ ! $(git diff -- */*/Cargo.lock) ]]"], env=linux_headless_env),
 ])
 
 mac_rel_css_factory = create_servo_factory([
@@ -229,7 +225,6 @@ mac_rel_css_factory = create_servo_factory([
                                 "--log-raw", "test-css.log"],
                        env=mac_test_env, logfiles={"test-css.log": "test-css.log"}),
     steps.ShellCommand(command=["gzip", "test-css.log"], env=mac_test_env),
-    steps.ShellCommand(command=["[[ ! $(git diff -- */*/Cargo.lock) ]]"], env=linux_headless_env),
 ])
 
 android_compile_env = dict({'ANDROID_SDK': '/home/servo/android-sdk-linux/',
@@ -239,7 +234,6 @@ android_compile_env = dict({'ANDROID_SDK': '/home/servo/android-sdk-linux/',
                            **linux_test_env)
 android_factory = create_servo_factory([
     steps.Compile(command=["./mach", "build", "--android", "--dev"], env=android_compile_env),
-    steps.ShellCommand(command=["[[ ! $(git diff -- */*/Cargo.lock) ]]"], env=linux_headless_env),
 ])
 
 android_nightly_factory = create_servo_factory([
@@ -258,7 +252,6 @@ gonk_compile_env = dict({'ANDROID_SDK': '/home/servo/android-sdk-linux/',
 
 gonk_factory = create_servo_factory([
     steps.Compile(command=["./mach", "build-gonk"], env=gonk_compile_env),
-    steps.ShellCommand(command=["[[ ! $(git diff -- */*/Cargo.lock) ]]"], env=linux_headless_env),
 ])
 
 doc_factory = create_servo_factory([