Remove invocation of bundle from inside Makefile

* when calling from withing git's Documentation dir, using bundler
  might not be desired.
* encapsulating recursive Makefile calls inside bundler breaks the job
  server of GNU make and generates a warning.

.travis.yml

@@ -4,7 +4,7 @@ cache: bundler
 before_install:
  - sh ci/install_po4a.sh
 script:
- - make all
+ - bundle exec make all
 addons:
   apt:
     packages:

Makefile

@@ -38,7 +38,7 @@ update-sources:
 define MAKE_TARGET
 
 $(1)_$(2):
-	@echo $lang;bundle exec $(MAKE) -C $(2) -f ../makefile.locale $(1) lang=$(2)
+	+$(MAKE) -C $(2) -f ../makefile.locale $(1) lang=$(2)
 
 $(1): $(1)_$(2)
 

README

@@ -161,7 +161,7 @@ compilation toolchain which you can get by running:
 
 Before you submit your changes do:
 
-    $ make all
+    $ bundle exec make all
 
 On systems with GNU gettext (i.e. not Solaris) and po4a this will try
 to merge translations with the source asciidoc files into translated