Update PROJECT.scl load()s with new magic label. (#640)

Author: gregestren

configurations/auto_configured_builds/alias/project_main/PROJECT.scl

@@ -1,10 +1,6 @@
 # A project file that automatically sets build flags for all targets in the
 # project and warns if the user sets any other flags.
-load(
-    "@bazel_tools//src/main/protobuf/project:project_proto.scl",
-    "buildable_unit_pb2",
-    "project_pb2",
-)
+load("//:project_proto.scl", "buildable_unit_pb2", "project_pb2")
 
 project = project_pb2.Project.create(
     # "WARN" means bazel emits a warning if the user sets flags to different

configurations/auto_configured_builds/compatible/PROJECT.scl

@@ -5,11 +5,7 @@
 # For example:
 #   --compilation_mode=dbg conflicts with --compilation_mode=opt
 #   --compilation_mode=dbg does not conflict with --//some:unrelated_flag=1
-load(
-    "@bazel_tools//src/main/protobuf/project:project_proto.scl",
-    "buildable_unit_pb2",
-    "project_pb2",
-)
+load("//:project_proto.scl", "buildable_unit_pb2", "project_pb2")
 
 project = project_pb2.Project.create(
     # "COMPATIBLE" means bazel errors if the user sets flags that conflict with

configurations/auto_configured_builds/strict/PROJECT.scl

@@ -4,11 +4,7 @@
 # form.
 #
 # See the "compatible" example for a more permissive variant.
-load(
-    "@bazel_tools//src/main/protobuf/project:project_proto.scl",
-    "buildable_unit_pb2",
-    "project_pb2",
-)
+load("//:project_proto.scl", "buildable_unit_pb2", "project_pb2")
 
 project = project_pb2.Project.create(
     # "STRICT" means bazel errors if the user sets any flags that aren't

configurations/auto_configured_builds/target_specific/PROJECT.scl

@@ -1,10 +1,6 @@
 # A project file that automatically sets build flags where diferent targets use
 # different flags.
-load(
-    "@bazel_tools//src/main/protobuf/project:project_proto.scl",
-    "buildable_unit_pb2",
-    "project_pb2",
-)
+load("//:project_proto.scl", "buildable_unit_pb2", "project_pb2")
 
 project = project_pb2.Project.create(
     buildable_units = [

configurations/auto_configured_builds/warn/PROJECT.scl

@@ -1,10 +1,6 @@
 # A project file that automatically sets build flags for all targets in the
 # project and warns if the user sets any other flags.
-load(
-    "@bazel_tools//src/main/protobuf/project:project_proto.scl",
-    "buildable_unit_pb2",
-    "project_pb2",
-)
+load("//:project_proto.scl", "buildable_unit_pb2", "project_pb2")
 
 project = project_pb2.Project.create(
     # "WARN" means bazel emits a warning if the user sets flags to different