[zeppelin] add temp directories generated by zeppelin-Rinterpreter to…

… gitignore

### What is this PR for?
When compile and test zeppelin-Rinterpreter, it will generate temp directories `/R` and `/tmp`
add them into `.gitignore`

### What type of PR is it?
Improvement

### Todos
N/A

### What is the Jira issue?
N/A

### How should this be tested?
N/A

### Screenshots (if appropriate)

### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No

Author: WeichenXu <[email protected]>

Closes apache#1297 from WeichenXu123/gitignore_add_R_tmp and squashes the following commits:

478a0dc [WeichenXu] gitignore add R tmp dir

.gitignore

@@ -47,6 +47,7 @@ zeppelin-web/bower_components
 # R
 /r/lib/
 .Rhistory
+/R/
 
 # project level
 /logs/
@@ -108,3 +109,6 @@ tramp
 
 # Generated by zeppelin-examples
 /helium
+
+# tmp files
+/tmp/