Make binaries executable

Split InstallFileName into InstallExecutable that does chmod +x
after copying the file.  Also remove InstallFile and rename
InstallFileName to InstallFile.

Test: m -j checkbuild
Change-Id: Id41ad4eafe521f6cd5d8cc250b7747ecb3da8dfc
diff --git a/python/installer.go b/python/installer.go
index 9c12f5f..04698c5 100644
--- a/python/installer.go
+++ b/python/installer.go
@@ -35,5 +35,6 @@
 var _ installer = (*pythonInstaller)(nil)
 
 func (installer *pythonInstaller) install(ctx android.ModuleContext, file android.Path) {
-	installer.path = ctx.InstallFile(android.PathForModuleInstall(ctx, installer.dir), file)
+	installer.path = ctx.InstallFile(android.PathForModuleInstall(ctx, installer.dir),
+		file.Base(), file)
 }