Description of problem:
nagios crashes on start in case template contains empty host property

Version-Release number of selected component (if applicable):
nagios-4.0.8-1.el7.x86_64

How reproducible:
always


Steps to Reproduce:
1. insert in a host template an empty property, e.g. line

  _EMPTY_PROPERTY

2. verify config -> ok
3. start nagios -> crash

Actual results:
*** Error in `/usr/sbin/nagios': free(): invalid pointer: 0x00007fa9681fad2c ***
======= Backtrace: =========
/lib64/libc.so.6(+0x7d1fd)[0x7fa9676fc1fd]
/usr/sbin/nagios(+0x365d1)[0x7fa9681a05d1]
/usr/sbin/nagios(clear_host_macros_r+0x80)[0x7fa9681a65b0]
/usr/sbin/nagios(clear_volatile_macros_r+0x26)[0x7fa9681a6a86]
/usr/sbin/nagios(run_async_service_check+0x3ca)[0x7fa96818745a]
/usr/sbin/nagios(run_scheduled_service_check+0xc1)[0x7fa968187731]
/usr/sbin/nagios(handle_timed_event+0x20b)[0x7fa96819d29b]
/usr/sbin/nagios(event_execution_loop+0x333)[0x7fa96819ddd3]
/usr/sbin/nagios(main+0xce6)[0x7fa96817e766]
/lib64/libc.so.6(__libc_start_main+0xf5)[0x7fa9676a0af5]
/usr/sbin/nagios(+0x14e7d)[0x7fa96817ee7d]
======= Memory map: ========
7fa967166000-7fa96717b000 r-xp 00000000 00:3c 375007720                  /usr/lib64/libgcc_s-4.8.3-20140911.so.1
7fa96717b000-7fa96737a000 ---p 00015000 00:3c 375007720                  /usr/lib64/libgcc_s-4.8.3-20140911.so.1
7fa96737a000-7fa96737b000 r--p 00014000 00:3c 375007720                  /usr/lib64/libgcc_s-4.8.3-20140911.so.1
7fa96737b000-7fa96737c000 rw-p 00015000 00:3c 375007720                  /usr/lib64/libgcc_s-4.8.3-20140911.so.1
7fa96737c000-7fa96767f000 rw-p 00000000 00:00 0 
7fa96767f000-7fa967835000 r-xp 00000000 00:3c 375007014                  /usr/lib64/libc-2.17.so
7fa967835000-7fa967a35000 ---p 001b6000 00:3c 375007014                  /usr/lib64/libc-2.17.so
7fa967a35000-7fa967a39000 r--p 001b6000 00:3c 375007014                  /usr/lib64/libc-2.17.so
7fa967a39000-7fa967a3b000 rw-p 001ba000 00:3c 375007014                  /usr/lib64/libc-2.17.so
7fa967a3b000-7fa967a40000 rw-p 00000000 00:00 0 
7fa967a40000-7fa967a43000 r-xp 00000000 00:3c 375008479                  /usr/lib64/libdl-2.17.so
7fa967a43000-7fa967c42000 ---p 00003000 00:3c 375008479                  /usr/lib64/libdl-2.17.so
7fa967c42000-7fa967c43000 r--p 00002000 00:3c 375008479                  /usr/lib64/libdl-2.17.so
7fa967c43000-7fa967c44000 rw-p 00003000 00:3c 375008479                  /usr/lib64/libdl-2.17.so
7fa967c44000-7fa967d45000 r-xp 00000000 00:3c 375008507                  /usr/lib64/libm-2.17.so
7fa967d45000-7fa967f44000 ---p 00101000 00:3c 375008507                  /usr/lib64/libm-2.17.so
7fa967f44000-7fa967f45000 r--p 00100000 00:3c 375008507                  /usr/lib64/libm-2.17.so
7fa967f45000-7fa967f46000 rw-p 00101000 00:3c 375008507                  /usr/lib64/libm-2.17.so
7fa967f46000-7fa967f67000 r-xp 00000000 00:3c 375003446                  /usr/lib64/ld-2.17.so
7fa967fb8000-7fa96815f000 rw-p 00000000 00:00 0 
7fa968164000-7fa968165000 rw-p 00000000 00:00 0 
7fa968166000-7fa968167000 rw-p 00000000 00:00 0 
7fa968167000-7fa968168000 r--p 00021000 00:3c 375003446                  /usr/lib64/ld-2.17.so
7fa968168000-7fa968169000 rw-p 00022000 00:3c 375003446                  /usr/lib64/ld-2.17.so
7fa968169000-7fa96816a000 rw-p 00000000 00:00 0 
7fa96816a000-7fa968214000 r-xp 00000000 00:3c 374606828                  /usr/sbin/nagios
7fa968413000-7fa968414000 r--p 000a9000 00:3c 374606828                  /usr/sbin/nagios
7fa968414000-7fa968417000 rw-p 000aa000 00:3c 374606828                  /usr/sbin/nagios
7fa968417000-7fa96841c000 rw-p 00000000 00:00 0 
7fa96849e000-7fa968522000 rw-p 00000000 00:00 0                          [heap]
7ffc6ef67000-7ffc6ef7c000 rw-p 00000000 00:00 0                          [stack]
7ffc6efab000-7ffc6efad000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]
Abgebrochen


Expected results:
No crash


Additional info:

nagios 3.x didn't crash