[DOC] Interrupt when program is stopped

[DOC] Interrupt when program is stopped

This patch changes the document that interrupt (ctrl-c) is not ignored
when the program is stopped.

When the interrupt was supported in remote target, people thought interrupt
is meaningless when the program is stopped.  See

  https://www.sourceware.org/ml/gdb/2005-11/msg00349.html
  https://www.sourceware.org/ml/gdb-patches/2005-11/msg00307.html

recently we find it is hard to preserve this feature "ignore interrupt
while program is stopped" when we fix some other bugs.  See
https://sourceware.org/ml/gdb-patches/2016-01/msg00039.html

so we think we can go to the simpler approach "not ignoring ctrl-c when
program is stopped".  As a result, we tweak the documentation here.

gdb/doc:

2016-01-12  Yao Qi  <yao.qi@linaro.org>

	* gdb.texinfo (Interrupts): Update the document on handling
	interrupt when program is stopped.