docs: Remove obsolete pre-3.10 kernel guidance

Drop Linux 2.6 build examples, an obsolete SRP initiator warning and
iSCSI daemon advice for a poll() bug fixed before the supported kernel
range.

Makefile

@@ -26,9 +26,6 @@ SHELL := /bin/bash
 # are not defined by the user, the current running kernel version is
 # used to define KVER.
 
-#export KDIR=/usr/src/linux-2.6
-#export KVER=2.6.x
-
 ifdef KDIR
     ifndef KVER
         KVER = $(strip $(shell						\

iscsi-scst/usr/iscsi_scstd.c

@@ -725,19 +725,8 @@ static void event_loop(void)
 			if (errno == EINTR)
 				continue;
 			else if (errno == EINVAL)
-				log_error("%s: poll() failed with EINVAL. Should "
-					"you increase RLIMIT_NOFILE (ulimit -n)? "
-					"Or upgrade your kernel? Kernels below 2.6.19 "
-					"have a bug, which doesn't allow poll() "
-					"to work with >256 file descriptors. See "
-					"http://sourceforge.net/mailarchive/forum.php?"
-					"thread_name=9392A06CB0FDC847B3A530B3DC174E7B0"
-					"55F1EF3%40mse10be1.mse10.exchange.ms&forum_"
-					"name=scst-devel for more details. Alternatively, "
-					"you can decrease iscsi_scstd.c::INCOMING_MAX "
-					"constant to a lower value, e.g. 128, then "
-					"recompile and reinstall the user space part "
-					"of iSCSI-SCST.", __func__);
+				log_error("%s: poll() EINVAL; increase RLIMIT_NOFILE",
+					  __func__);
 			else
 				log_error("%s: poll() failed: %s", __func__,
 					strerror(errno));

scst/Makefile

@@ -19,7 +19,6 @@
 
 SHELL=/bin/bash
 # Decide to use which kernel src. If not specified, is current running kernel.
-#export KDIR=/usr/src/linux-2.6
 
 SCST_DIR=src
 

srpt/Testing.txt

@@ -72,9 +72,7 @@ Index: srpt/src/ib_srpt.c
  	ch->req_lim_delta = 0;
 
 * Verify that a SCSI reset works properly by running the following command
-  on an initiator system (note: with kernel version 2.6.37 and before the
-  command below triggers a bug in the Linux SRP initiator -- see also
-  https://bugzilla.kernel.org/show_bug.cgi?id=13893):
+  on an initiator system:
 
   (target)
     echo add debug > /sys/kernel/scst_tgt/targets/ib_srpt/trace_level