Fix crash on bad symbol size in ELF header

[dthaler]

ELFIO expects symbols to be either 16 bytes (if 32-bit) or 24-byte (if 64-bit)
But it uses the entry size in the header to compute the number of symbols.
In this test file, they don't match, which resulted in a crash before this fix, and an error after it.

Signed-off-by: Dave Thaler dthaler@microsoft.com

[coveralls]

Pull Request Test Coverage Report for Build 2455606236

• 4 of 4 (100.0%) changed or added relevant lines in 2 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.002%) to 70.136%

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Files with Coverage Reduction	New Missed Lines	%
../../../../../usr/include/boost/container/detail/next_capacity.hpp	2	55.56%

Totals
Change from base Build 2452331854:	-0.002%
Covered Lines:	5909
Relevant Lines:	8425

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💛 - Coveralls